Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

All times are local (= UTC + 12 hours)

05/1970 (CSLP 47-70) Series of powerful eruptions form new crater on 12 May

Card 0943 (22 May 1970) Series of powerful eruptions form new crater on 12 May

A series of powerful eruptions opened a new 200-m round crater at the top of the cone of Karymsky Volcano on . . . 12 May. On 20 May a team of [volcanologists from the Institute of Volcanology] visited the eruption area by helicopter and collected the first rock samples. Within the next few days a new expedition will depart for the volcano and seismologists will make on the spot observations and study the erupting volcano.

Information Contact: Institute of Volcanology, Petropavlovsk.

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06/1970 (CSLP 47-70) Details of 12 May eruption; ash explosions continuing every 2-3 hours

Card 0950 (01 June 1970) Details of 12 May eruption; ash explosions continuing every 2-3 hours

"Paroxysmal phase . . . began on 12 May. Eruptive ash cloud reached height of ~6 km, length 100 km, ashfall area 3,000 km², total ash amount 3 million tons. Nuees ardentes observed at distance 1-1.5 km, andesite dacitic lava flow reach length of about 1.5 km. Its volume 4 million cubic meters. Present activity ash explosions each 2-3 hours. Eruption continues."

Information Contact: Y.M. Doubik, Institute of Volcanology, Petropavlovsk.

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09/1970 (CSLP 47-70) Daily ash explosions

Card 1018 (25 September 1970) Daily ash explosions

The following cable was received [on] 25 September 1970. "Ash explosions 1 km height, periodicity of explosions one per day."

Information Contact: Y.M. Doubik, Institute of Volcanology, Petropavlovsk.

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06/1975 (CSLP 46-75) Explosion on 10 May sends plume 1.5 km high

Card 2201 (23 June 1975) Explosion on 10 May sends plume 1.5 km high

The eruption of Karymsky . . . began with a powerful explosion on 10 May 1975. A huge cloud of ash and gas rose to a height of 1,500 m at 0415 GMT, and again on 14 May at 2300 GMT. The explosions were preceded by volcanic tremors recorded since 7 May at the seismic station located 3.5 km from the crater.

Information Contact: Y.M. Doubik, Institute of Volcanology, Petropavlovsk.

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04/1976 (SEAN 01:07) Frequent explosions eject tephra and gases

Karymsky erupted during April. Scientists registered 60-80 explosions a day and believed that the plug in the crater's vent was being broken. Ash, slag, and gases were discharged from the crater.

Information Contact: Y. Doubik, IV.

Further Reference. Zharinov, I.A., and Firstov, P.P., 1985, Activity, seismic regime, and crust inclination at Karymsky volcano during the summer of 1976: Volcanology and Seismology, no. 2, p. 93-95.

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08/1979 (SEAN 04:08) Explosions and lava flows

Tass reported on 31 July that explosions every 2-3 minutes produced 1-km-high ash clouds, and two lava flows were moving down the flanks.

Information Contact: Tass News Agency.

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10/1982 (Ref 1984a) Lava dome fills crater before being destroyed by explosions

Lava dome growth continued in 1982, filling the crater by mid-year. Small to moderate explosions were frequent January-July. Less frequent but more violent explosions occurred in August and September, then decreased gradually and ended by 10-11 October. The lava dome was destroyed, leaving a bowl-shaped crater similar to that prior to the 1978 eruption.

Reference. Ivanov, B.V., Chirkov, A.M., Dubik, Yu. M., Khrenov, A.P., Dvigalo, V.N., Razina, A.A., Stepanov, V.V., and Chubarova, O.S., 1984, Active volcanoes of Kamchatka and Kurile Islands: status in 1982: Volcanology and Seismology, v. 6, p. 623-634 (English translation of paper in Volcanology and Seismology, 1984, no. 4, p. 104-110).

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09/1983 (Ref 1984b) Weak fumarolic activity without seismicity

The following, from Ivanov and others (1984b), was published in SEAN 10:04. [After the eruption ended in October 1982, only weak fumarolic activity, without accompanying seismicity, was observed during the following 11 months. As of September 1983, the summit crater was 160 x 120 m, elongate NE-SW, and post-eruption collapse had deepened it to 60 m (Ivanov and others, 1984).]

Reference. Ivanov, B.V., Gavrilenko, G.M., Dvigalo, V.N., Ovsyannikov, A.A., Ozerov, A.Yu., Razina, A.A., Tokarev, P.I., Khrenov, A.P., and Chirkov, A.M., 1984, Activity of volcanoes in Kamchatka and the Kurile Islands in 1983: Volcanology and Seismology, v. 6, p. 959-972 (English translation of paper in Volcanology and Seismology, 1984, no. 6, p. 114-121).

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04/1985 (SEAN 10:04) Apparent new lava flow photographed by astronauts

On 3 May, Space Shuttle astronauts photographed a feature that appeared to be a short, stubby lava flow extending from the summit crater toward the Pacific coast. The feature was a black area with a length (roughly several hundred meters) 2-3 times its width, and boundaries that were sharply defined against the snow cover. No eruption plume was observed.

Information Contact: C. Wood, NASA, Houston.

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03/1990 (BGVN 15:03) Slight thermal activity

The volcano was generally quiet during a 2 February overflight (figure 1). Pre-existing thermal areas were visible in the S and SW parts of the crater, although the vent was snow-covered. Slightly warm zones were also noted on the upper S flank.

Information Contacts: B. Ivanov, IV.

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08/1993 (BGVN 18:08) Small steam emissions in summit crater

No activity was observed during an overflight on 24 August, but small steam emissions in the S and SW part of the summit crater were noticed by SVE members who climbed the cone.

Information Contacts: H. Gaudru, SVE, Switzerland.

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05/1995 (BGVN 20:05) Increased seismicity in mid-April

Increased seismicity was recorded below Karymsky during 8-14 April, although it is uncertain whether this increase is indicative of an eruption in the near future. A large fumarolic area lies near the summit.

The number of seismic stations has decreased recently, and Kamchatka Volcanic Eruptions Response Team operations are still suspended due to lack of funds.

Information Contacts: Institute of Volcanic Geology and Geochemistry; Alaska Volcano Observatory.

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01/1996 (BGVN 21:01) Explosive eruption from Karymsky Lake and new crater at summit

Periods of seismic unrest have occurred several times in the past 12 months, including one episode in April 1995, and the volcano usually emits a continuous steam plume. Based on recorded seismic activity, an eruption apparently began during 1700-1900 on 1 January. Russian aviation sources reported an ash plume to 7 km altitude at approximately 1130 the next day. A satellite image at 1400 on 2 January showed that the plume had extended at least 200 km SE and S of the volcano. Several aviation notices (SIGMETs) were issued concerning the ash plume. GMS satellite imagery revealed multiple ash emissions on 2 January, with the cloud height estimated at ~7 km. Satellite data on 3 January continued to show multiple low-level (below 5,400 m) ash bursts of short duration that drifted S and dissipated within an hour.

When the volcano was visited by Vladimir Kirianov and Yuri Doubik of the Institute of Volcanic Geology and Geochemistry between 1330 and 1630 on 3 January, they discovered that the initial eruption had vented from the N end of Karymsky Lake. The lake occupies the 5-km-diameter late-Pleistocene Akademia Nauk caldera, ~5 km S of Karymsky volcano proper. However, by the time of their visit activity had shifted to Karymsky volcano where a new crater had formed on the SSW side of the summit, adjacent to the old crater. The new crater, approximately the same size as the old crater, produced explosions every 1-5 minutes that fed a thick black ash plume to an altitude of ~2.5 km moving E. Fresh ashfall was widespread throughout the 5-km-wide Karymsky caldera and for a considerable area to the E and N. Karymsky Lake was yellow-gray in color and mostly covered by steam and vapor. The Karymsky River, which drains the lake to the N, was completely buried in ash and no longer visible; a new beach with numerous fumaroles marked the former source of the river. Very strong seismic activity associated with the eruption included one M 6.5 earthquake on the first day of the eruption. Seismic stations as far as 110 km from the volcano recorded the activity.

By 5 January the new summit crater was over twice the size of the old crater. A thick black ash plume had been observed the previous two days erupting explosively from the new crater to altitudes ranging of 2,400-5,500 m. Seismicity on 6 January indicated continued explosions every 1-3 minutes. Karymsky Lake remained yellow-gray and covered by steam and vapor. Seismicity through 12 January was interpreted to reflect continued, but less explosive, eruptive activity.

Information Contacts: Tom Miller, Alaska Volcano Observatory; Vladimir Kirianov and Yuri Doubik, Institute of Volcanic Geology and Geochemistry; Synoptic Analysis Branch, NOAA/NESDIS, USA.

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02/1996 (BGVN 21:02) Ongoing explosions eject steam and minor ash

Following the main eruptive period in early January, Karymsky had produced one to several small explosions a day. The explosions consisted mainly of steam with minor ash rising to heights <=1.5 km above the summit. Daily explosions continued until at least ~7 March. The lava flow erupted in January stopped growing during early February and continued cooling. The Institute of Volcanic Geology and Geochemistry (IVGG) reported that during the first week of March, Karymsky lake had a temperature of 23°C with a hotter area (32°C) located at its N end.

Ground reports noted one eruptive pulse at 2330 on 29 February; it sent ash and steam to ~4 km altitude; satellite imagery failed to detect this pulse. Simulated trajectory for plumes showed them generally blowing S to SSW.

Information Contacts: Vladimir Kirianov and Yuri Doubik, IVGG; Alaska Volcano Observatory; Synoptic Analysis Branch, NOAA/NESDIS, USA.

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03/1996 (BGVN 21:03) More details about the early January eruptions

According to the Institute of Volcanology (IV), the eruption on 2 January began around 0800. This activity was preceded by an upsurge in seismicity that started in April 1995. At 1926 on 31 December 1995, a M 5.8 earthquake occurred in the Kronotsky gulf, 50-60 km NE of the volcano. On 1 January at 2057 an earthquake of M 5.2 in the Karymsky region was followed at 2157 by a M 6.9 event centered ~25 km S of the volcano. During the next day there were more than 10 aftershocks of M >= 5.0. On 2 January at 1540, a group of IV volcanologists arrived by helicopter. Eruptive centers were observed near the summit and 5-6 km S in Karymsky Lake (maximum depth 115 m), which fills the Akademii Nauk caldera.

The eruption began with formation of a vent with a diameter of 20-30 m, located 50 m below the summit. Violent emissions of ash-rich gas jets rose to 1 km from another vent on the SW slope. Steam-and-gas jets, occasionally with black-colored matter, were also ejected to several hundred meters from beneath the surface of Karymsky Lake. The presumed eruptive center was 100-200 m from the shore in the NW sector of the lake. Turbulent steam-and-gas plumes rose 5-6 km above the surface from a 200-m-diameter area. Ice covering the lake had completely melted.

On 3 January the near-summit vent increased in size to 50 m in diameter. Gas and steam blasts alternated with ash ejections from the two simultaneously active vents on the volcano. Ash was usually ejected from the upper vent, and a white-colored plume was emitted from the lower vent. Ash ejections lasted 2-3 minutes, and gas blasts lasted 1.5-2 minutes. An ash-and-gas column rose 1-1.2 km and was blown E and SE by the wind. The surface of Karymsky Lake steamed intensely, sending clouds 800-1,000 m above the lake. Areas of green water were visible through breaks in the clouds, and a newly-formed black beach was seen. In the N and NE sector of the lake a narrow spit, beginning from the source of the Karymsky river and extending 250-300 m to the center of the lake, had formed. The water level in the lake had dropped a few meters. The upper reaches of the river had dried up, but on 2 January waves from the submarine eruption (up to 10 m high or more) overflowed the N shore, flooding a wide valley 1.5 km below the source. During a surveillance flight on 4 January, large areas of the valley were covered by black mud. The beach contained three fumarolic vents along the NE-trending fault zone. Within a radius of 500-800 m of the source of the Karymsky River, the surrounding snow-covered hills contained thousands of holes with diameters ranging from 10 cm to 1.5-2 m formed by lithic blocks ejected from the lake. The water level of the lake continued to fall because of intense evaporation.

Light-gray dacitic ash covered an area of about 150-200 km². At a distance of 8 km from the volcano fractions ranging from 0.16 to 0.06 mm dominated. Estimates made by S.A. Fedotov indicated that on 2 and 3 January the ash ejection rate from the summit crater reached 3-4 tons/second.

Routine observations from 2 January through 11 February showed that the climactic phase of the subaqueous eruption continued for no more than 12-15 hours. That eruption consisted of frequent explosions during which a vapor-gas mixture with lithic material was ejected to the surface. In the N sector of the lake at the shore W of the Karymsky River, damaged trees provided evidence of two eruptive sources 500-600 m from each other. This zone contained the main concentration of bomb material ejected from the lake. A portion of the shoreline (150-200 m long and 5-15 m wide) E of the river sank several meters into the lake. The main eruption center was 500 m from the shore, but smaller peripheral centers were also observed. As a result of the eruption, in the NNW sector of the lake, a beach in the form of a wide 0.4 km² cape was produced, as well as a narrow spit extending SE from the old shore. The length of the new shoreline was 2.4 km, and a large shoal was observed around the new peninsula. According to the preliminary estimates, the ejected deposits in the lake are at least 1 km² in area and 5-10 x 10⁶ m³ in volume.

Thermal springs that discharge at the S shore of Karymsky Lake were destroyed by ejecta from this eruption, and several new mud pots were formed; chemical composition of the solutions was unchanged. Near the center of the new beach, composed of sand-gravel and bomb material, a chain of five explosive vents with diameters from 1.5 to 30 m was observed. At the N end was a thermal site with a diameter of ~50 m that exhibited intense vapor emission and was covered by sublimates; visiting scientists detected a hydrogen sulfide odor. A dry funnel with a diameter of ~3 m and high gas emission at a temperature of 97°C was in the center of this site. Other explosion funnels had water at a depth of 1.2-1.5 m with temperatures from 33 to 70°C. The three funnels closest to the lake and on the opposite shore had gas emissions with temperatures of 97-98°C.

On 4 January run-off from the lake ceased owing to damming by ejected material. Analyses of water samples from the lake, river, and various hot springs in the area indicated that there had been chemical contributions to the lake water by an underlying magma body.

Information Contacts: G.A. Karpov, Ya.D. Muravyev, R.A. Shuvalov, S.M. Fazlullin, and V.N. Chebrov, Institute of Volcanology, Far East Division, Russian Academy of Sciences, Petropavlovsk-Kamchatsky, 683006, Russia.

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05/1996 (BGVN 21:05) Eruptions continue through April; more details of early January activity

Eruptions began on 2 January from the summit of Karymsky and from the lake (Karymsky Lake) within the Akademia Nauk caldera (figure 2), previously considered to be extinct (BGVN 21:01-21:03). Eruptive activity at [Karymsky] continued through the end of April.

Precursory seismicity. Large tectonic earthquakes in the Kronotsky Gulf have historically been among the precursors to eruptions from Karymsky and Maly Semiachik volcanoes. At 1926 on 31 December 1995, a M 5.6 earthquake occurred in the Kronotsky Gulf (50-60 km NE) at a depth of ~60 km. Earthquake swarms are common beneath the large (50 x 35 km) Karymsky Volcanic Center, but an unusually large swarm started on the evening of 1 January with hypocenters to depths of 80 km (figure 3). These followed a M 5.2 foreshock, and at 2157 a shallow M 6.9 earthquake took place centered ~25 km S of Karymsky; this was the largest earthquake recorded beneath the Kamchatkan volcanoes during the past 50 years. Scientists from the Institute of Volcanology and the Kamchatkan Experimental-Methodical Seismological Department of Geophysical Survey, Russian Academy of Sciences, flew to the epicentral zone of the continuing earthquake swarm and observed the onset of the eruption.

Early eruptions at Karymsky volcano. On the afternoon of 2 January the eruption began on Karymsky's upper SW flank 50 m below the old summit crater and from the Akademia Nauk caldera lake, ~6 km S (figure 4). Ash and gas clouds from the summit vent fed a plume (figure 5) rising to 1 km above the crater; the ash-flow rate was estimated to be several cubic meters per second. The eruption cloud extended E towards the ocean and ashfall was visible 40-50 km away.

On the evening on 3 January another crater formed on Karymsky; it looked like a 30-m-diameter amphitheater open to the SW. Sub-vertical Vulcanian explosions occurred from this crater to an altitude of 1 km. Over the next few days, explosions sent gas-and-ash emissions 300-1,100 m high almost every minute.

During the first three days of the eruption, ~500-800 x 10³ tons of solid materials, including ash, lapilli, cinder, and bombs, were ejected at Karymsky. During the next 2-3.5 months ~3-4 x 10³ tons of andesite-dacite tephra (SiO2 61%) and a small amount of bombs were ejected. An area with a radius of 15-20 km was covered by an ash layer several millimeters thick. The layer's thickness increased along the ashfall axis, reaching 20-30 mm at 4-5 km from the source.

Early eruptions at Akademia Nauk caldera lake. Violent subaqueous explosions on 2 January took place several times every hour in the N part of the 5-km-wide Akademia Nauk caldera lake (figure 6). Explosion clouds rose to 8 km altitude, but most of the tephra fell back into the lake. Ash from Karymsky Lake covered Akademia Nauk volcano and its surroundings. The head of the Karymsky River had its valley and adjacent flood-lands inundated by high water and mud flows.

Although the Akademia Nauk caldera lake had been ice-covered during the winter, after the January explosions water temperature reached 25°C, pH decreased from 7.5 to 3.1-3.2, and mineralization increased from 0.1 g/l to 0.9 g/l. Thermal water compositionally similar to those of the Karymsky springs started to discharge at a new shoal in the N part of the lake. According to preliminary estimates, ~0.015 km³ of material was supplied to the lake during the eruption.

After the lake water had cleared, a subaqueous deposit around the main explosion vent (with a diameter of 1 km) was observed. The N part of the deposit, ~1 km², was exposed at the surface, forming an arched spit with the adjoining peninsula (figure 7). According to preliminary estimates, ~5-10 x 10⁶ m³ of tephra including sand and rounded fragments of various sizes, and many bombs, formed the deposit there. Their composition ranged from basaltic andesite to andesite-dacite. The volume of deposits on the bottom of the lake is much greater.

Activity through April. During the ensuing days in January, the eruption style at Karymsky dropped to 5-6 explosions reaching 500-900 m high every hour. More vigorous single explosions were exceptional. On 13-14 January, a block-lava flow from the flank crater traveled 400 m, was 50-70 m wide, and averaged 6-10 m thick. In late January the interval between explosions started to increase from 30 minutes to 2-3 hours.

In February only several explosions were observed each day (figure 8). In late February the number of explosions increased to 5-6/hour, but their intensity decreased. In March the number of explosions decreased but their intensity increased. In April the number of explosions increased. For example, on 23 April they took place every 5 minutes. Two additional lava flows were emitted from the flank crater in April.

A dense geodetic network developed since 1972 at the Karymsky Volcanic Center has been measured repeatedly. During the past 20 years, a horizontal extension of Akademia Nauk caldera was observed that may have indicated filling of a magma chamber under the volcano. Measurements made in February and March revealed an extension of 232 cm along the 3.5-km base and subsidence of 70 cm near the area of subaqueous explosions in the caldera lake.

Karymsky Volcanic Center. Karymsky and Akademia Nauk are part of the 50 x 35 km Karymsky Volcanic Center (sometimes referred to as the Zhupanovsky volcano-tectonic depression). Located in the Eastern Kamchatka volcanic belt, 30 km from the Kronotsky Gulf and Pacific Ocean, this center contains 21 volcanic edifices, six calderas, and two historically active stratovolcanoes, Karymsky and Maly Semiachik.

The 5-km-diameter Karymsky Caldera formed 7,800 years ago and the Karymsky cone has been growing in the center of the caldera for 5,300 years, ejecting andesitic and dacitic materials. Historical reports on Karymsky's eruptions have been available since 1771. During that period of time, more than 20 prolonged eruptions were separated by quiet periods as long as 10 years. The most recent previous eruption continued from 1970 to 1982.

Akademia Nauk caldera, which was named by the famous Russian volcanologist Vladimir Vlodavetz in 1939, is located immediately to the S in the SW part of the Karymsky Volcanic Center. Its activity began about 50,000 years ago. The N part of the caldera is occupied by Karymsky Lake (4 km wide, 12.5 km² in area, and 80 m deep). The Akademia Nauk chloride-sodium springs, with 1.3 g/l mineralization and temperatures >250°C in the interior part of the hydrothermal system, discharge along the lake's S shore.

Information Contacts: S.A. Fedotov, V.A. Budhikov, G.A. Karpov, M.A. Maguskin, Ya.D. Muravyev, V.A. Saltykov, and R.A. Shuvalov, Institute of Volcanology, Russian Academy of Sciences, Petropavlovsk-Kamchatsky, 683006, Russia.

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06/1996 (BGVN 21:06) Above background seismicity correlating to weak Strombolian eruptions

Seismicity remained above background in June and the first half of July, and was indicative of continued low-level Strombolian eruptive activity. Gas-and-ash explosions occurred about every 5-20 minutes, generating ash-and-steam plumes to an altitude of 500-3,000 m. Regular reports from KVERT (via AVO) resumed in June after funding problems in Russia halted communications in December 1994 (BGVN 19:11).

Information Contacts: Tom Miller, Alaska Volcano Observatory; Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry.

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08/1996 (BGVN 21:08) Explosions send plumes up to 3 km high

Seismicity remained above background in late July and August, and was indicative of continued low-level Strombolian eruptive activity. Gas-and-ash explosions occurred about every 10-25 minutes, generating ash-and-steam plumes to an altitude of 1,800-3,000 m.

Information Contacts: Tom Miller, Alaska Volcano Observatory; Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry.

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09/1996 (BGVN 21:09) Explosions send bombs to 500 m and plumes up to 5 km high

During September and the first half of October, seismicity remained above background and was indicative of continued low-level Strombolian eruptive activity. Gas-and-ash explosions occurred every 3-25 minutes, commonly generating ash-and-steam plumes 300-700 m high. However, the eruptive activity increased on 13 October. Volcanic bombs were ejected to 500 m above the crater; eruptive plumes from separate explosions rose to 3-5 km above Karymsky and extended >200 km NE and E. AVO analysis of satellite imagery confirmed a hot spot at the volcano.

Information Contacts: Tom Miller, Alaska Volcano Observatory; Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry.

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10/1996 (BGVN 21:10) Elevated seismicity in October-November indicates continued eruption

During the second half of October and November, seismicity remained above background and was indicative of continued low-level Strombolian eruptive activity. On the afternoon of 13 November, a pilot report indicated vigorous but low-level activity; satellite imagery also showed a well-developed plume traveling ~140 km SE. On 15 November AVO analysis of satellite imagery confirmed a hot spot at the volcano and a plume extending 140 km E.

Information Contacts: Tom Miller, Alaska Volcano Observatory; Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry.

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12/1996 (BGVN 21:12) Elevated seismicity persists; up to 300 explosions daily

Although no visual observations were made, during December and 1-20 January seismicity remained above background in a manner that suggested continued low-level Strombolian eruptions. Seismic data indicated that up to 300 explosions occurred each day.

Information Contacts: Tom Miller, Alaska Volcano Observatory; Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry.

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02/1997 (BGVN 22:02) Satellite images show hot spot; above-background seismicity continues

No direct visual observations were made during February and 1-24 March. Above-background seismicity suggested ongoing low-level Strombolian eruptions. Satellite imagery examined by the Alaska Volcano Observatory (AVO) showed a persistent hot spot at the summit and occasional low-level ash plumes.

Information Contacts: Alaska Volcano Observatory; Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry.

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03/1997 (BGVN 22:03) Ash plumes reported by aircraft pilot

No direct visual observations were made during 25 March-25 April, however the above-background seismicity suggested ongoing low-level Strombolian eruptions. On 14 April an airline pilot reported an ash plume at 6.1 km, but no plume was detected on GMS-5 satellite imagery.

Information Contacts: Tom Miller, Alaska Volcano Observatory; Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry.

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06/1997 (BGVN 22:06) Elevated seismicity indicating continued Strombolian activity

Seismicity remained above background for the three-week interval ending on 27 July. Although visual observations were absent, seismicity indicated continued low-level Strombolian eruptive activity of the kind that has characterized the volcano for more than a year.

Information Contacts: Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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09/1997 (BGVN 22:09) Strombolian activity continues with 3-4 explosions/hour; small lava flow

On 2 August, V. Kirianov visited the volcano by helicopter and reported continuation of the low-level Strombolian activity that has characterized the volcano for more than a year. A blocky lava flow (60 m wide and 350 m long) was observed moving from the crater down the W slope during 2-10 August. During early August- early October, seismicity remained above background levels. Low-level Strombolian activity continued through mid-October. Gas-and-ash explosions during this period occurred at a frequency of 3-4/hour, with plumes usually rising to 150-600 m, rarely as high as 1,000 m.

Information Contacts: Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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11/1997 (BGVN 22:11) Low-level Strombolian activity continues

During 13 October-24 November seismicity remained above background level; low-level Strombolian eruptive activity that has continued since January 1996 (BGVN 21:01) consisted of gas and ash explosions occurring every 20 minutes, sending ash and steam 200-400 m above the crater. During 24 November- 29 December there was elevated seismicity and explosions every 20-30 minutes that sent ash and steam 300-400 m above the crater. On 14 December, the level of concern was downgraded to yellow from orange, indicating that the volcano's activity was less indicative of a major eruption.

Information Contacts: Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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01/1998 (BGVN 23:01) Low-level Strombolian activity continues through January

The Kamchatka Volcanic Eruptions Response Team (KVERT) reported continuation of the low-level Strombolian activity that has characterized Karymsky for more than two years. Seismicity remained just above background level. Gas-and-ash explosions during 29 December to 31 January occurred of every 30 minutes, with plumes usually rising 300-400 m. An ash advisory issued by the Washington Volcanic Ash Advisory Center (VAAC) reported an eruption 26 January that produced an ash cloud rising to 3,500 m. No other details of this eruption were available, and satellite imagery did not show evidence of the plume.

Information Contacts: Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory; NOAA/NESDIS Satellite Analysis Branch (SAB), USA.

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02/1998 (BGVN 23:02) Ongoing gas-and-ash explosions

Seismicity remained above background level and low-level Strombolian activity sent ash and steam 300-400 m above the crater during 27 January-1 March. During 27 January-8 February, gas-and-ash explosions occurred every 30-40 minutes. During 9 February-1 March, 70-100 gas-and-ash explosions occurred per day. On 9 February, 11 tectonic earthquakes were recorded ~10 km S of Karymsky.

Information Contacts: Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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03/1998 (BGVN 23:03) Gas-and-steam explosions and above-background seismicity

Seismicity remained above background level during 2 March-5 April and low-level Strombolian activity continued. As many as 70-100 gas-and-ash or gas-and-steam explosions occurred daily. Ash and steam rose 300-400 m above the crater during the first week of March.

Information Contacts: Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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04/1998 (BGVN 23:04) Strombolian eruptions continue; satellite imagery may indicate lava effusion

Seismicity at Karymsky remained above background levels during April and May. The low level Strombolian activity characteristic of the past 2 years continues. Violent gas explosions numbered between 70 and 200 daily. Deeper events predominated over explosive events.

Satellite imagery available to the Alaska Volcano Observatory (AVO) showed that on 17 April a long, thin steam plume had extended over 100 km from Karymsky. Also, a distinct thermal anomaly (about 40°C), well above background temperatures, had appeared at the summit 18 April. These features may indicate a small renewal of lava effusion.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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06/1998 (BGVN 23:06) Continuing gas-and-ash explosions and lava flow observed during 14-15 July

Through analysis of seismic data, the Kamchatkan Volcanic Eruptions Team (KVERT) detected a change in the volcano's behavior. For the past 2 years, Karymsky characteristically produced low-level Strombolian activity, including more than 100 earthquakes and gas explosions each day. After 10 July the explosive events began to accompany 1-4 minute segments of harmonic tremor.

A visit on 14-15 July disclosed gas-and-ash explosions to heights of 400-600 m above the crater every 8-10 minutes on average. More vigorous gas-and-ash explosions to 1 km occurred about every 2 hours. Lava continued to flow. During the night of 14-15 July, and the following morning, weak ashfall was observed 3.5 km from the crater. Later that morning, a series of ash explosions occurred with a periodicity of ~5 minutes. The color-coded hazard status remained at yellow.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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08/1998 (BGVN 23:08) Explosions and blowouts on 26 July

Seismicity remained above background levels during 26 July-1 September. Low-level Strombolian activity, including 100-200 earthquakes and gas explosions each day, continued to characterize activity at the volcano. On 26 July, gas-and-ash explosions reached heights of 400-600 m and occasionally 1,000-1,200 m above the crater every 5-10 minutes on average. Lava continued to flow from the crater (BGVN 23:04 and 23:06). The color-coded hazard status remained at Yellow.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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10/1998 (BGVN 23:10) Strombolian eruptions and elevated seismicity continue

On 5 October, the Kamchatka Volcanic Eruptions Response Team reported that seismicity remained above background level. The low-level Strombolian eruptive activity that has characterized the volcano for more than two years continued. About 100-200 earthquakes and gas explosions occurred every day.

On 24 October Tass reported that a Russian-Japanese expedition of volcanologists had finished their work on Karymsky. The participants had spent two weeks at a location 3 km from the mountain studying seismic, acoustic, and other phenomena related to the eruption.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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11/1998 (BGVN 23:11) Strombolian eruptions continue, ash column seen on 24 November

Seismicity remained above background levels during 1 November-7 December. Low-level Strombolian activity, including 100-200 earthquakes and gas explosions each day, continued to characterize activity at the volcano. On 24 November a pilot in the vicinity reported an explosive event that sent an ash column 6 km above the summit. The color-coded hazard status remained at Yellow.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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12/1998 (BGVN 23:12) Satellite image shows ash plume 16 December

Seismicity remains elevated. The low-level Strombolian eruptive activity that has characterized the volcano for the past two years continued during December. About 300-400 earthquakes and gas explosions occur every day. Satellite imagery on 16 December showed an ash-poor plume extending 200 km E. No change in seismicity was noticed. The level of concern color code remained yellow.

Information Contacts: Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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01/1999 (BGVN 24:01) Strombolian eruptions continue; thermal anomaly seen on satellite image

The low-level Strombolian eruptive activity that has characterized Karymsky for more than two years continued during January. About 300-400 earthquakes and gas explosions occur every day. The color-coded alert level continued at yellow.

Satellite imagery obtained by Alaska Volcano Observatory from 14 January showed a strong thermal anomaly on the volcano, but no change in seismicity was noticed. Seismic information for 28-31 January was not available owing to technical problems.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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03/1999 (BGVN 24:03) Ash eruptions continue during February

Seismicity remained above background during February and March, and the Level of the Concern Color Code remained at Yellow. Low-level Strombolian eruptive activity that has characterized the volcano for more than 3 years continued with ~150-200 daily earthquakes and gas explosions.

An ash plume observed on 10 February rose ~5 km above the summit. Satellite images on 15 and 17 February showed a thermal anomaly. Small earthquakes close to Karymsky Lake began to be recorded on 7 February. According to a pilot's report, an ash plume on the morning of 25 February rose as high as 3,500 m.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry; Tom Miller, Alaska Volcano Observatory.

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07/1999 (BGVN 24:07) Ongoing explosions resume 7 August after brief quiet

The low-level Strombolian eruptive activity that has characterized the volcano for more than three years continued from 24 May through 26 July. Earthquakes and gas explosions ranged over 25-70/day until 5 July when seismicity began decreasing to just above background levels. During the week of 5 July to 12 July, the number of earthquakes and gas explosions decreased to ~5-10/day. Probable pyroclastic flows occurred on 24 and 25 July. Overall activity continued to decrease and on 2 August, after more than 3 years of eruptive activity, the volcano returned to its normal state.

However, on 5 August, seismicity under the volcano increased and more than 70 weak to moderate gas explosions were recorded. On 7 August, after 10 days of quiescence, eruptive activity was renewed and the number of explosions exceeded 300/day.

Eco-tourists visited the volcano between 8 and 10 July (guided by Guy de Saint-Cyr of Aventure et Volcans of Lyon, France and Alexei Choustrov of Top Sport Travel, St. Petersburg, Russia) and reportedly made helicopter flights above the crater and a landing at their base camp. For 8 July the group reported no visible activity in the central crater and a very viscous lava flow (Merapi type) with some incandescent zones escaping from the collapsed part of the crater. But at 1705 on 9 July, they noted a violent detonation with simultaneous explosions on the two summit craters and a ~200-m-diameter eruptive column rising vertically to ~700 m altitude. All of Karymsky volcano disappeared under an ash cloud with a shower of 1-m3-sized blocks crashing down and rolling to the foot of the cone and halting less than 100 m from their base camp. According to their report, from 2000 on 9 July to 0600 on 10 July, an active lava flow accumulated at the foot on the W side of the crater.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Tom Miller, Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological & Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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11/1999 (BGVN 24:11) Eruptive activity gradually decreases, then stops in late December

The low-level strombolian eruptive activity that has characterized the volcano for more than three years gradually decreased after August until seismicity returned to background levels, and by late December there were no explosions. The eruption began on 2 January 1996 (BGVN 21:01) following an eruption from the Akademia Nauk caldera lake the previous day.

During the week of 9-15 August, steam-and-ash plumes were observed in satellite imagery extending as far as 75 km downwind at an altitude of 500-1,000 m above the crater. The number of gas-and-ash explosions was still more than 300/day the next week, with the plume rising 300-600 m above the volcano. During the last week of August through 5 September, the number of explosions was more than 75/day, with plumes to heights of 300-1,000 m above the volcano. Visual observations by KVERT staff on 1 and 5 September confirmed that explosive activity occurred every 10-20 minutes.

The number of gas-and-ash explosions decreased from 130 on 6 September to 80 on the 12th, but the plumes continued to rise 300-1,000 m above the volcano. That rate continued until the week of 20-26 September, when the average number of daily explosions decreased to 60. The number of explosions was 60-75/day during the next two-week reporting periods, through 10 October. During the week of 11-17 October the explosion rate decreased once again, to 20-35/day, although plume heights remained at 300-1,000 m. The number of explosions increased slightly, to 20-50/day, during 5-18 November, but then dropped the following week to 10-20/day and then only 2-5/day. During the week ending on 2 December, gas and ash explosions numbered 1-10/day.

The nearest seismic station (KRY) was out of order during 4-18 December. According to the regional seismic network, no strong events occurred during that period. The station was restored to operation on 19 December. As of 30 December seismicity at the volcano had decreased to background levels. About 1-2 local earthquakes occur every day and the volcano has returned to its normal state. At the end of December seismicity was at background levels of about 1-2 local earthquakes/day.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Tom Miller, Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological & Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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04/2000 (BGVN 25:04) Low-level eruptive activity; intense ash-and-gas explosions in April

This report covers the period from January-April 2000. As of 28 April 2000, KVERT (Kamchatkan Volcanic Eruption Response Team) temporarily suspended operations because of a lack of funding. Throughout January and early February, seismicity was at background levels with about 1-5 small local earthquakes each day. However, after two months of quiescence, seismic activity beneath the volcano renewed at 0635 on 12 February; seismic data indicated the occurrence of a probable, short-lived gas-and-ash (or gas) explosion as a 5-minute-long seismic signal was recorded by the nearest seismic station (KRY). As a result of this activity, the hazard level was raised to Yellow.

Following this event, an average of 5-10 seismic events/hour occurred, mainly corresponding to explosions along with a few blowouts and pyroclastic flow (?) signals. After 1200 on 15 February, seismicity increased to 40 events/hour. A continuous series of seismic events (pyroclastic flows?) were registered from 1620 to 1810 on 15 February, but satellite images at 1715 and 1855 that day did not show a plume rising above the weather clouds at ~4 km altitude. From 1800 on 15 February to 1340 on 16 February, activity varied from 40-60 events/hour at the end of which a new 80-minute-long series of seismic events was registered. Subsequently, during 1500-1750, 200 events occurred and, at 1750, strong low-frequency, 4-minute-long events were registered. Activity decreased from 40 to 20 events/hour from 1800 on 16 February until 1200 on 17 February. A satellite image from 0630 on 17 February, the first clear image that the Alaska Volcano Observatory had received since the increase of activity on 12 February, showed no plume, but a thermal anomaly covered at least four pixels with a maximum temperature of 40°C.

The low-level Strombolian eruptive activity that has characterized the volcanism for much of the past four years continued for the remainder of February and throughout March. The number of gas-and-ash explosions decreased from 600/day to 25/day during late February. From 1230 to 1620 on 18 February weak volcanic tremor was registered. According to pilot reports on 20 and 21 February, these explosions sent material up to 1,500 m above the volcano. The number of gas-and-ash explosions varied from 5 to 300/day (although 5-50/day was most typical) through March; suspected small pyroclastic flows were occasionally detected.

At 0625 and 2336 on 3 April and 0743 on 4 April, seismic data indicated short-lived ash-and-gas explosions more intense than those previously recorded. These explosions probably occurred during 3-6-minute-long seismic events recorded by the nearest seismic station (KRY). However, during the following week, no more than three small events/day were recorded and the hazard level was returned to Green. This level of activity continued through April with occasional 2-15-minute-long seismic events, related rock avalanches, and possible short-lived explosions.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Tom Miller, Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological & Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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09/2000 (BGVN 25:09) Likely pyroclastic flow on 25 June; increase in seismic events and explosions

This report covers Karymsky's activity from June through mid-October 2000. KVERT (Kamchatkan Volcanic Eruption Response Team) resumed reports at the beginning of June after a month-long shutdown due to funding deficiencies. The seismic events per day and number of explosions varied throughout the period, but decreased to background levels by the end of September. On 10 June, 25 short-lived weak explosions occurred, although the average number of explosions per day during that week remained low. During 19-29 June, seismicity increased when up to 17 events occurred per day. The number of weak explosions also increased during 19-29 June when up to six explosions occurred per day. On the afternoon of 25 June intense explosions were recorded that suggested a pyroclastic flow. Other than this, no significant volcanic activity occurred. KVERT maintained the Level of Concern Color Code at Green for the entire interval.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Tom Miller, Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological & Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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08/2001 (BGVN 26:08) Increased seismicity from December 2000 through September 2001

Since the activity reported from June through mid-October 2000 (BGVN 25:09), the Kamchatkan Volcanic Eruption Response Team (KVERT) reported that seismic activity at Karymsky remained mostly at background levels, with a few episodes of increased seismicity.

On 20 December 2000 around 0915 shallow earthquakes under the volcano were accompanied by short-lived explosions. At 2150 the same day a pilot confirmed the presence of ash at the summit of the volcano and mud traces from melting snow on the edifice slopes. The Concern Color Code was increased from Green (volcano is dormant; normal seismicity and fumarolic activity) to Yellow (volcano is restless; eruption may occur) until 29 December.

On 2 and 28 February several shallow seismic events took place, including a 5-minute-long series of weak shallow earthquakes on 28 February. During March, small shallow earthquakes and one episode of weak high-frequency spasmodic tremor were registered. On 12 March a high-frequency signal lasted for 90 minutes. On 28 March, from 1205 to 1300, an intense series of earthquakes with magnitudes up to ~3 was registered. Several local low-frequency earthquakes occurred during the end of March and beginning of April. Around 20 April, more than 40 earthquakes with magnitudes up to ~2.5 occurred. Since then through at least September 2001, seismic activity at Karymsky has remained at background levels with the exception of 23 August, when 30 earthquakes were registered.

General Reference. Khrenov, A.P., and others, 1982, Eruptive activity of Karymsky Volcano over the period of 10 Years (1970-1980): Volcanology and Seismology, no. 4, p. 29-48. Tokarev, P.I., 1990, Eruptions and seismicity at Karymskii volcano in 1965-1986: Volcanology and Seismology, v. 11, p. 117-134 (in English).

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Tom Miller, Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological & Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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03/2002 (BGVN 27:03) Elevated seismicity; possible explosions and avalanches in March 2002

Episodes of increased seismicity occurred during December 2000 through September 2001 (BGVN 26:08). Since then seismic activity at Karymsky has remained mostly above background levels. The Concern Color Code remained at Yellow ("volcano is restless") through at least late March 2002. Apparent steam plumes were seen in satellite imagery during January-March 2002.

On 4 January 2002, the Kamchatkan Volcanic Eruption Response Team (KVERT) reported above-background seismicity during the previous week, with 40 to 80 weak local earthquakes occurring per day. Several shallow seismic events suggested gas-ash explosions. Beginning at 1200 on 10 January the number of local earthquakes increased noticeably. During 11-14 January about 200 weak local shallow seismic events occurred per day.

During late January through at least March 2002, the seismic station typically recorded approximately 10 local shallow earthquakes per hour. Around 24 January, the earthquakes became slightly stronger. The character of the seismicity during mid-March suggested weak ash-gas explosions and avalanches.

The Tokyo VAAC reported that on 1 February at 1810 an eruption produced an ash cloud that reached ~7.5 km above the summit and drifted to the E; however, the cloud was not visible on satellite imagery. On 13 February at 0945 a pilot reported an ash cloud to ~3.5 km above the volcano extending to the W. Again, this cloud was not visible on satellite imagery; it may have been a single burst that dissipated rapidly.

No ash was detected in satellite images during the report period; only steam and possible airborne volcanic aerosols were visible during late February. Thermal anomalies and plumes were visible on AVHRR satellite imagery throughout the report period (table 1).

Table 1. Thermal anomalies and plumes visible on AVHRR satellite imagery at Karymsky during January through March 2002. Courtesy KVERT.

     Date          Time        Size       Max. band-3      Background
    (2002)        (local)  (# of pixels)  temperature      temperature
        Visible plume

    19 Jan         1659         2           31.6°C           -21°C
    19-25 Jan                  2-4        -3.7 to 35.0°C   -16 to -25°C
    21 Jan         1614
        Steam plume extending 45 km SE
    27 Jan         1711         1           47.7°C           -22°C
    28 Jan         1646
        Small steam plume extending 30 km NE
    3-8 Feb                    2-10       49.7 to -7°C     -15 to -30°C
    5-6 Feb                              Steam plume extending 100-150 km E
    8 Feb          0536         4            5.7°C           -22°C
    13 Feb         0538         4            0.1°C           -23°C
    13 Feb         1202         4           -1.7°C         -22 to -28°C
    13 Feb         1708         4            ~49°C           -20°C
        20-km long steam plume moving SW
    14 Feb         1644         5             39°C            -8°C
        Small plume extending N
    17 Feb         0544         1             -3°C           -22°C
    18 Feb         1649         4             32°C           -10°C
        Short plume extending NE
    19 Feb         1622
        Small steam plume extending 100 km E
    20 Feb         0613         4           24.9°C           -24°C
    21 Feb         0550         4           -4.2°C           -25°C
    22 Feb-1 Mar               1-4        12 to 40°C       -10 to -27°C
    22 Feb         1650
        Very diffuse cloud observed that could be related to volcanic aerosols
    27 Feb         1635
        20-km long faint steam plume extended E
    2-8 Mar                    1-4        1 to 15°C        -17 to -24°C
    6 Mar          1708
        Bifurcated steam plume; first branch extended 10 km NE and the second
        branch extended 20 km SE
    16-22 Mar                  2-4        -6.8 to 35.6°C   0 to -20°C
    19-20 Mar
        Small steam/aerosol plume extending SE
    22 and 25 Mar              1-3        -6.8 and 14°C      -20°C

General Reference. Khrenov, A.P., and others, 1982, Eruptive activity of Karymsky Volcano over the period of 10 Years (1970-1980): Volcanology and Seismology, no. 4, p. 29-48.

Tokarev, P.I., 1990, Eruptions and seismicity at Karymskii volcano in 1965-1986: Volcanology and Seismology, v. 11, p. 117-134 (in English).

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Tokyo Volcanic Ash Advisory Center (VAAC),Tokyo, Japan (URL: http://www.ssd.noaa. gov/VAAC/OTH/JP/messages.html).

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06/2002 (BGVN 27:06) Explosions eject ash to 3 km above summit during April and July 2002

Seismicity at Karymsky was above background during late March through at least mid-July 2002. Local shallow events occurred at the same rate previously reported in BGVN 27:03 (~10 events per hour). The rate increased briefly during mid-May to ~10-15 events per hour. The character of the seismicity indicated that weak gas-and-ash explosions and avalanches possibly occurred. Thermal anomalies and occasional plumes were visible on satellite imagery throughout the report period (table 2).

Table 2. Thermal anomalies and plumes visible on AVHRR satellite imagery at Karymsky during 30 March-9 July 2002. No airborne ash was detected in any image. Courtesy KVERT.

    Date(2002)        Time          Size         Max. band-3     Background
                     (local)    (# of pixels)    temperature     temperature
        Visible plume

    30 Mar             --            --             13°C        -15 to -20°C
    31 Mar             --            --             --                --
        Faint thermal anomaly visible through cloud cover.
    09 Apr             --             4             29°C             0°C
    12 Apr-19 Apr      --            2-5            --                --
    17 Apr            1807            2             29°C            -3°C
        Faint aerosol/steam plume trended SE.
    20 Apr             --             3             23°C        -5 to -20°C
    22 Apr             --             5             30°C             3°C
    26 Apr-03 May      --            1-6            42°C           0- ~10°C
        Possible faint aerosol/steam plume trended SE,
        visible at 1704 on 28 April.
    03 May             --            3-4           13.4°C           -8°C
    04 May             --            3-4            40°C            -1°C
        Small aerosol/steam plume visible trended S at 1800.
    09 May            1740            2            37.5°C            4°C
        Faint ash-and-gas plume visible extended 20 km to the SE.
    10 May-17 May      --            2-4           ~50°C            2-7°C
    10 May            0727           --             --               --
        Ash-and-steam plume visible trended 50 km to the S.
    13 May            1744           --             --               --
        Faint steam/aerosol plume extended ~60 km to the SE.
    20 May             --             1             16°C            -2°C
        Faint plume extended 30 km to the SE at 0647.
    22 May             --             2            ~49°C             7°C
    24 May            0651            3            16.4°C           -2°C
    01 Jun             --             1             11°C             0°C
    02 Jun             --             3             49°C             6°C
    09 Jun            0708           2-4           43.5°C          -1.5°C
    15 Jun             --             3            ~49°C             17°C
        Karymsky lake visible on image at temperature of 33.6°C,
        six pixels square, warmest to the W.
    20 Jun             --             3             38°C             17°C
    23, 25, 27 Jun     --            1-3         10 - ~49°C        1 - 18°C
        Steam/gas plume extended 35 km to the W on 25 June.
    29 Jun-30 Jun      --            1-4         15 - ~49°C       -4 - 25°C
    01 Jul-02 Jul
        Small steam plume extended ~50 km to the NE on 1 July.
    6, 8-9 Jul         --            1-3        ~25 - 31°C        5 - 11.5°C

According to a pilot's report, at 1115 on 15 April an explosion ejected ash to a height of 3.0 km above the volcano. MODIS imagery on 17 April revealed at least five traces of ashfall extending to ~25 km in various directions.

During a helicopter flight on 28 April, observers reported an ash explosion to 500 m above the crater. Ash deposits were visible on the W (most intense) and E flanks of the volcano. A new ~100-m-high cone was visible on 28 April inside the active crater.

On 10 May the new cone was visible along with a lava flow 1.3 km down the S-SW slope of the volcano (figure 9). It reached ~300 m wide. The flow was unusual because it had an andesitic composition, rather than the typical basaltic composition that was common in lava flows down the SW flank during 1996-2000. Seismic data on 29 June indicated a possible ash-and-gas explosion to a height of ~4.0 km at 1631. On 9 July at 1032, a helicopter pilot reported a plume to a height of 3.0 km. The Concern Color Code remained at Yellow throughout the report period.

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Tokyo Volcanic Ash Advisory Center (VAAC),Tokyo, Japan (URL: http://www.ssd.noaa.gov/VAAC/).

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09/2002 (BGVN 27:09) 3-km-high plumes, seismicity, and three new lava flows through September 2002

Frequent plumes (including 15 April and 9 July ash clouds to 3.0 km above the volcano), a new intracrater cone, and a 1.3-km-long lava flow were seen during 1 January-9 July 2002 (BGVN 27:03 and 27:06). This report first highlights events described in 10 July-September 2002 updates. During this interval Karymsky produced 3-km-tall plumes, restless seismicity, and three new lava flows. Next, a separate section of this report presents photos of Karymsky and adjacent Akademia Nauk caldera taken in September 2000 and in May 2002. This report also cites a fundamental reference volume on the topic of the 1996 eruption, Fedotov (1998), which includes a preface and ten papers.

Activity during 10 July-September 2002. Seismicity during this interval generally stood well above background levels, very often at a value of ~10 earthquakes per hour. During nearly every week of the reporting interval, geophysicists suggested that the character of the seismicity might indicate weak ash-and-gas explosions and avalanches. Weak thermal anomalies were often observed on AVHRR satellite imagery and, in the majority of cases, no ash was detected. In contrast, satellite imagery on 25 July indicated a possible, small, SW-directed ash plume. On 26 July, a thermal anomaly reached 2 pixels in size.

During 27 July-2 August, local, shallow seismic events decreased, dropping from 250 to 150 events per day. During 30 August-6 September and 13-24 September there were 200-300 local shallow earthquakes occurring per day (compared to 150-250 per day in August). In early September estimates suggested that explosions rose ~1 km above the summit.

Observations on 8 September revealed three new small lava flows on the volcano's S and SE slopes. On satellite imagery a thermal anomaly was visible but ash was not. The character of the seismicity indicated ash-and-gas explosions rising ~1 km above the volcano and gas blow-outs. On 16 September at 1217 a short-lived explosion created an ash-and-gas plume; observers on an aircraft aloft estimated the plume top's height at ~3 km altitude.

Photographs and brief retrospective on the 1996 eruption. Figures 10 and 11 provide overviews of the Karymsky stratovolcano (also written as Pra-Karymsky) and adjacent areas to the S on 26 September 2000 and 10 May 2002 respectively. Both these aerial photos were provided by Victor Ivanov (Russian Academy of Sciences). The former was taken ~4 years after the complex 1996 eruption (see BGVN 21:01-21:03 and 21:05; and Fedotov, 1998).

In overview, that eruption consisted of a 1 January 1996 earthquake swarm (with events to M 6.9) followed a day later with simultaneous eruptions from two vents 6 km apart, one at the stratovolcano's summit, the other at Akademia Nauk caldera in the N end of Karymsky lake. The latter consisted of a submarine phreatomagmatic eruption that deposited a low conical ring composed of pyroclastics. The subaerial portion of those deposits encircled the vent forming a ~600-m-wide crater in the cone's center. The cone also extended to the lake shore, thus forming a peninsula. The eruptive event included or was associated with base surges, tsunamis, surface ruptures, and secondary eruptions on the new peninsula. The eruption also left the lake with pH of 3.2 and its outlet into the Karymsky river obstructed by the new deposits. Several months later the new deposits eroded, resulting in massive mudflows down the Karymsky river. At the submarine vent eruptive products were predominantly basaltic; some fine ash was andesitic; late-stage rhyolites occasionally formed inclusions within basalts and bombs with basaltic jackets.

The photos were taken from perspectives on the volcano's N side. Several months after the dam-breaking event, the partly eroded pyroclastic deposits took the form of a squat U-shaped peninsula with two arms extending hundreds of meters into the lake. The circular segment along the middle of the peninsula's shoreline is part of the original cone's arcuate rim. Towards the left of the peninsula lies a conspicuous bay that leads to the outflow channel and the Karymsky river (the latter is most apparent on figure 10). Figure 11 shows that two years later the pyroclastic deposits in the lake more closely resemble lines rather than broad zones due to the partial cover of ice and snow.

The 1996 eruption at Karymsky and the Akademia Nauk caldera may have been a response to the injection of fresh basaltic magma from a deeper magmatic source. Later stages of the eruption at Karymsky have continued more than 6 years through this reporting interval.

During the underwater eruption in 1996 all of the lake's ice was broken and melted. Along the lake shore many new hot springs appeared. After the underwater eruption on the bottom of the lake many sources of heat and degassing appeared. The eruption triggered an ecological catastrophe during which all fish in the lake died.

During the winter 1996-1997 the water of the lake remained warm and devoid of ice. Usually ice completely disappears only in June or July. Lake ice returned in subsequent winters. Figure 10 (26 September 2000) shows light-colored patterns on the lake's surface that signify the presence of local ice accumulating there with the approach of winter. Figure 11 documents the dominance of ice on Karymsky lake's surface, still intact from the previous winter when photographed. The May 2002 lake surface also contained some ice-free zones. Their presence suggested the continued existence of post-eruptive heat sources on the lake bottom. These areas were possibly rich in algae and micro-organisms.

Reference. S. A. Fedotov, S.A., 1998, The 1996 eruption in the Karymsky volcanic center and related events: Special issue of Volcanology and Seismology, v. 19, no. 5, p. 521-767 (L.N. Rykunov, Ed. in Chief; Preface and 10 papers; English translation), Gordon & Breach Science Publishers (ISBN 0742-0463).

Information Contacts: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Victor Ivanov, Institute of Volcanology Far East Division, Russian Academy of Sciences, Petropavlovsk-Kamchatsky, 683006, Russia (Email: vivanov@kcs.iks.ru).

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05/2003 (BGVN 28:05) Frequent ash plumes generated from October 2002 through May 2003

According to the Kamchatka Volcanic Eruptions Response Team (KVERT), the alert level Color Code remained at Yellow (volcano is restless; eruption may occur) from October 2002 to 27 February 2003, when it was dropped to Green (volcano is dormant; normal seismicity and fumarolic activity). The level was raised again to Yellow in March, lowered to Green on 29 March, and raised to Yellow on 18 April, where it remained through May. Seismicity was above background levels until 20 February, after which it fluctuated between at and above background levels until 16 May, when seismicity remained above background levels. All times are local (= UTC + 11 hours, + 12 hours after 26 October).

Activity during October 2002. From 4 to 31 October, ~200-250 local shallow seismic events occurred per day. The character of the seismicity indicated ash-and-gas explosions to heights of 1,000 m above the volcano (~2,500 m altitude) and gas blow-outs. A faint 10-km-long plume extending SSE was visible in an AVHRR satellite image; no ash was detected. Seismicity on 25-26 October indicated possible vigorous gas emissions lasting 5-10 minutes, with the probability of a lava flow. At 1350 on 31 October, pilots reported that an ash plume rose 4 km and extended SE. According to seismic data from the Kamchatka Experimental and Methodical Seismological Department (KEMSD), the character of seismicity after 1400 on 31 October indicated a moving lava flow. At 1314 on 31 October, the MODIS satellite image showed a large bright thermal anomaly at the volcano and a plume ~60 km long that extended WSW. At 1100 on 1 November, pilots reported that an ash plume rose 4 km and extended SE.

Activity during November 2002. Local shallow seismic events totaled ~200-250 each day. The character of the seismicity indicated ash-and-gas explosions to heights of 1,000-2,000 m above the volcano and vigorous gas emissions lasting 5-10 minutes. At 1605 on 1 November, a 50-km-long plume was observed extending E in satellite imagery; no ash was detected. According to data from KEMSD, at 2357 on 20 November, a seismic event lasting 20 minutes indicated that ash explosions to heights of 1,000 m above the crater and hot avalanches possibly occurred. On 27 November, a >100-km gas-and-steam plume extending ESE from the crater of the volcano was observed in MODIS satellite imagery. Helicopter observations by KVERT scientists at 1151 on 1 December identified an ash plume to ~500 m above the crater extending SE.

Activity during December 2002. Local shallow seismic events totaled ~190-230 each day. The character of seismicity indicated that ash-gas explosions to heights of 1,000 m above the volcano (~2,500 m altitude) and vigorous gas emissions lasting 5-10 minutes were possibly occurring. The top of the volcano and its SE flank were covered with recent ashfall and debris from continuing Vulcanian / Strombolian eruptions. The old crater was covered by the new cinder-ash cone. On 12 December, two sectors of ash falls extending S and SE from the volcano were noted in a MODIS satellite image.

Activity during January 2003. Local shallow seismic events totaled ~110-200 each day. The character of seismicity indicated that ash-gas explosions to heights of 1,000 m above the volcano (~2,500 m or 8,200 ft. ASL) and vigorous gas emissions lasting 5-10 minutes were possibly occurring. From 1559 until 1609 on 8 January, a series of shallow events that possibly indicated hot avalanches were registered. On 9 January, a ~50-km plume extending ESE from the volcano was noted.

Activity during February 2003. The alert level Color Code remained at Yellow until 27 February, when it was lowered to Green (volcano is dormant; normal seismicity and fumarolic activity). According to satellite data from Russia, a weak thermal anomaly was noted on 3 February. Seismic activity was at background levels on 20-23 February.

Activity during March 2003. The alert level Color Code was raised to Yellow as the activity of the volcano slightly increased. Seismic activity was at background levels on 13-18 March and slightly above background levels on 19 March when seismic data indicated possible hot avalanches. Weak volcanic earthquakes were also registered on this day. According to MODIS-satellite data from Russia and the USA, ash deposits extending more than 30 km SW from the volcano on 17-20 March and gas-steam plumes drifting more than 15 km NW and SW on 18 March and on 20 March, respectively, were noted. Seismic activity dropped to background levels for the week of 20 March. According to satellite data from Russia, a weak thermal anomaly was observed on 25 March, and a gas-and-steam plume extending 10 km ESE was noted on 28 March. According to helicopter observations on 31 March by the Institute of Volcanology (IV), Far East Division, Russian Academy of Sciences, the large old active crater of the volcano and its black ESE flank were noted, but the new cinder-ash cone was not seen. This cone was probably destroyed and its products formed ash-deposits extending >35 km ESE, which were noted on the 17-18 March MODIS-satellite images.

Activity during April 2003. The alert level Color Code was dropped to Green during the week of 29 March-4 April, when seismic activity was at background levels. Seismicity rose above background levels during the week of 18-24 April, when ~40-100 volcanic earthquakes per day were recorded, and the hazard status was raised to Yellow. The character of the seismicity indicated ash-and-gas explosions up to 1,000 m above the crater. According to satellite data from Russia, ash deposits up to 35 km or longer extended in different directions on 19-22 April. According to observers from IV, on 18-24 April occasional ash-gas explosions up to 2,500 m above the crater occurred each day, and on 21 April, an ash-gas plume rose 1,500 m. Seismic activity was above background levels on 24-27 April and at background levels on 27-30 April. During 24-26 April 50-100 volcanic earthquakes per day were registered. The character of the seismicity indicated that three eruption events (possibly ash-and-gas explosions and rock avalanches) occurred on 24 April. According to satellite data from Russia, wide ash deposits longer than 35 km and three narrow ash deposits less than 5 km long extending SE and W and SW from the volcano, respectively, were noted on 25 April and 28-29 April. According to observers from IV FED RAS, on 24 April, an ash-gas plume rose 2,500 m above the crater.

Activity during May 2003. The alert level Color Code remained at Yellow for the month, with intermittent explosive eruptions continuing. Occasional explosions up to 1,500 m above the volcano, producing ash, were considered to be possible, as well as ashfall within a few tens of kilometers. Seismic activity was at background levels during 3-16 May. According to satellite data from Russia, the summit of the volcano was black on 4 May. For the week of 10-16 May, seismic data indicated that 10 ash-and-gas explosions reached heights up to 1,000 m above the crater, and hot avalanches possibly occurred. According to satellite data from the USA and Russia, a weak 1-pixel thermal anomaly on 14 May, and strips of ash deposits extending >10 km to the S, SSE and SE on 14-15 May were noted. Seismicity was above background levels on 16-30 May.

During 18-21 May, 150-320 local shallow events occurred per day. The character of the seismicity indicated ash-and-gas explosions to heights of 1,000 m above the volcano, gas blow-outs and hot avalanches. According to satellite data from the USA and Russia, a 2-4-pixel thermal anomaly was observed during 18-22 May. Ash deposits on snow E and SE of the volcano were noted on 18 May. Gas-steam plumes extending up to 45 km NE and N of the volcano on 19 and 21 May were noted. For the week of 24-30 May, 280-330 local shallow seismic events occurred per day. The character of the seismicity indicated ash-and-gas explosions to heights of 1,000 m and gas blow-outs. A thermal anomaly continued to be observed. On 25-26 May, gas-and-steam plumes extending 15-115 km SSE from the volcano were noted. Ash deposits on the snow in a different direction from the volcano were noted on 26-27 May.

Information Contacts: Olga Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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07/2003 (BGVN 28:07) May-July ash plumes; affiliated seismicity and satellite thermal anomalies

Dark ash was observed on the NE, SE, and W flanks of the volcano on 30 May in a MODIS (moderate resolution imaging spectroradiometer) Terra image. Intermittent explosive eruptive activity at Karymsky occurred from early June into mid-August 2003, with seismic activity above background levels. Between 90 and 270 local shallow events occurred per day. The character of the seismicity indicated that ash-and-gas explosions to heights of 1,000-2,000 m above the volcano (2,500-3,500 m altitude) and gas blow-outs possibly occurred. On the morning of 17 July a strong, long duration (86 minutes), seismic event occurred that possibly resulted from a large pyroclastic flow or the onset of a new lava emission. Satellite data confirmed the continuing activity (table 3).

Table 3. Thermal anomalies at Karymsky from AVHHR (advanced very-high resolution radiometer) satellite images and visual observation during June and July 2003. Courtesy Kamchatka Volcanic Eruptions Response Team (KVERT).

    Date(s)         Thermal Anomaly   Comments
                       (pixels)

    3 June             2 (faint)      No ash plume observed
    22-24 June           1-4          --
    27 June               --          Short narrow plume to NE
    28-30 June           1-4          --
    4, 6-9 July          1-4          --
    14-15 July           2-3          --
    13, 16 July          2-5          No ash plumes observed
    19 July               --          Ash plume to SW
    25, 27-29 July       1-3          --

Information Contacts: Olga Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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11/2003 (BGVN 28:11) Intermittent explosions and elevated seismicity through November

From late August through 5 December seismic activity at Karymsky was above background levels (100-230 events per week) and intermittent explosions continued. The Level of Concern Color Code was Yellow through most of September and October, with a week at the higher Orange status during 3-10 October. The color code was raised to Orange again on 31 October and remained at that level through 5 December. Thermal anomalies identified in satellite data were usually 1-4 pixels in size, with a maximum of 6 pixels on 30 August, and 10, 11, 14, and 16 October. However, the weather was frequently cloudy after 12 September, obscuring observations.

Ash explosions rising up to 4.0 and 4.7 km were observed from aircraft on 29 August. About 2 hours of continuous spasmodic tremor (6.0 x 10^-6 m/s) on 30 August, followed by the detection of a thermal anomaly (6 pixels) less than an hour later, may have been caused by a pyroclastic flow.

On 9 and 10 September, continuous high-frequency spasmodic tremor and a series of shallow seismic events indicated possible ash-and-gas explosions to heights of 1.5-2.0 km above the volcano. A gas-and-steam plume extending 100 km E was noted on 9 September. On 14 September an ash-and-gas plume was seen rising 500 m above the crater. On 23 September there was an explosive ash plume up to 5 km altitude according to visual data from the Institute of Volcanology.

The number of shallow seismic events increased during 4-24 October to weekly highs of 350; these events indicated possible ash-and-gas explosions to heights of 1-1.5 km. Ash plumes extending 60 and 30 km SE and NE were observed on 4 and 7 October, respectively. An extensive gas-and-steam plume extending 85 km SE was noted on 10 October. Continuous high-frequency spasmodic tremor detected for almost an hour on 10 October probably indicated pyroclastic flows. Ash plumes extending 45-50 km NW were observed on 16 October. On 31 October, a possible plume extending ~65 km NNE was observed in a satellite image. Gas-and-steam plumes with possible minor ash ~40-60 km long were detected on 20, 21, 24, and 26 November; clouds obscured the volcano on other days.

Information Contacts: Olga Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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12/2003 (BGVN 28:12) Late 2003 explosions to at least 3.5 km above summit

The intermittent explosions and elevated seismicity reported in BGVN 28:11 continued through December 2003. The Tokyo Volcanic Ash Advisory Center (VAAC) reported, for the period 28 November-5 December, that intermittent explosive eruptions emitted ash up to ~ 3.5 km altitude. The Kamchatkan Volcanic Eruption Response Team (KVERT) reported on 12 December 2003 that intermittent explosive eruptive activity at Karymsky was continuing, with occasional explosions sending ash up to 3.5 km above the volcano and local ashfall possible. Seismicity was above background levels, with 200-250 shallow long-period events per day during the previous week and possible ash-gas explosions rising up to 1-1.5 km above the volcano. Seismic data showed, at 0745 on December 5, a possible ash-gas explosion up to 4 km. Satellite data from 5-10 December showed a 1- to 5-pixel thermal anomaly over the volcano.

KVERT reported similar conditions for the week ending 19 December, with ash to 1-2.5 km above the crater and 160-240 events per day. On 16 December, they reported possible ash plumes up to 3 km above the crater and 1- to 5-pixel thermal anomalies on 11-17 December. These conditions continued during the week ending 26 December, with seismic events fluctuating at 40-200 per day and ash-and-gas plumes rising 1-2 km over the volcano. The number of earthquakes decreased during 18-20 December and increased during 21-24 December, with probable ash explosions to 3.5 km on 21 December.

At 0359 on 23 December and 1605 on 24 December possible explosions with pyroclastic flows were recorded. A 1- to 3-pixel thermal anomaly was observed by satellite on 21-22 and 24-25 December. For the week ending 2 January 2004, local shallow earthquakes took place 200-270 times per day with possible ash-gas explosions to 2-3.5 km. Possible explosions accompanied by pyroclastic flow were recorded on 25, 29, and 31 December; a 1- to 4-pixel thermal anomaly was also observed. On 29 December a very narrow gas-steam plume extended 97 km SE. The color code alert remained at orange during the month.

Information Contacts:.Olga Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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04/2004 (BGVN 29:04) Intermittent gas-ash explosions and elevated seismicity continue

Intermittent explosions and seismicity above background levels, as also reported in BGVN 28:11, continued from 1 January to mid-April 2004, a time interval when the Level of Concern remained at Orange. Occasional explosions occurred without warning, sending ash as high as ~ 7000 m altitude and yielding ashfall locally and beyond the volcano. Ash deposits were detected extending in essentially all directions on various days during the report period. Clouds frequently obscured visual observation of the volcano.

During January 2004 the daily number of local shallow earthquakes varied from lows of 40-80 to highs of 200-300. Similarly, in February, shallow events varied from lows of 30-40 to highs of 160-200. However, in March, particularly after the early part of the month, the highest daily numbers rose to 240-380. The highest daily numbers reached still higher during April, to as high as 300-470.

Up to five ash-gas explosions occurred on specific days during each month. These explosions sent plumes to altitudes of ~ 3-5 km during January (although pilot reports sometimes estimated higher plumes, to 5.5 to 7 km altitude). Plumes rose to ~ 2.5-6.5 km during February and March, and dropping to ~ 2.5-3.5 km during April. Thus, although more daily earthquakes occurred during April, the plume heights then appeared lower than in January-March.

During the week ending 16 January, an ash plume observed by pilots of a local airline rose to 7 km altitude and extended to the S-SW. Pilots also reported ash plumes rising up to 5.5 km altitude on 9 and12 February. On 11 February, an ash cloud rose to 10 km altitude and drifted 60 km from the volcano. Reports describing 20 February noted ash deposits extending about 35 km S.

According to satellite data from the USA and Russia, thermal anomalies of 1-4 pixels were observed during January and 1-6 pixels during February and March. However, the number of pixels increased from 1 to 10 during early April, the same period when the number of shallow earthquakes was increasing.

Information Contacts: Olga A. Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

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06/2005 (BGVN 30:06) Several ash plumes, including two to ~ 8 km altitude, during mid-2005

During 1 January to mid-April 2004 (BGVN 29:04), ash-and-gas explosions and gas plumes were observed and seismicity remained generally above background levels. From May to the beginning of September 2004, seismic activity remained above background levels, varying over this time from 100-800 small shallow earthquakes per day. Ash-and-gas explosions and gas plumes to a maximum height of 7.5 km were frequent. On 1 September 2004 an increase in activity led the Kamchatka Volcanic Eruptions Response Team (KVERT) to raise the Concern Color Code from Yellow to Orange. From September to December 2004, seismicity remained above background levels, and ash-and-gas explosions and ash plumes were frequent. On 12 November the hazard status was lowered to Yellow.

Increasing seismicity, rock avalanches and possible ash plumes to 2.5 km altitude led KVERT to raise the Concern Color Code to Orange again on 7 December 2004. On 28 December, an observed eruption at Karymsky produced a plume composed primarily of gas and steam, but with some ash, that rose to ~ 1 km above the crater. Thermal anomalies were also visible on satellite imagery on 27 and 28 December. On 30 December the Tokyo VAAC reported that a plume was present up to ~ 8 km altitude extending SW.

There were no seismic data from 12 December 2004 till late January 2005. Through January and February thermal anomalies were frequently visible on satellite imagery. Seismicity remained above background levels from February 2005 through July 2005.

Through March and April 2005, ash-and-gas explosions and gas plumes were frequent. Ash deposits extended 10-15 km S and SW of the volcano. On 20 April, volcanic bombs rose to 50 m above the crater, and ash fell to the NE on 21 April. On 26 and 27 April, Strombolian activity was seen in two of the volcano's craters; volcanic bombs rose to ~ 300 m above the craters. Ash fell to the SE on 22-23 April and pyroclastic-flow deposits were seen on the NNW flank of the volcano. During May 2005, ash-and-gas explosions and plumes were again frequent, and a thermal anomaly continued to be visible on satellite imagery.

Due to a decrease in seismic and volcanic activity during 3-10 June, KVERT decreased the alert level from Orange to Yellow. Seismic activity increased starting on 22 June. Ash explosions up to 3,000 m altitude traveling SW were observed by pilots. According to seismic data, about 10 ash-and-gas plumes and avalanches occurred at the volcano. On 23 June KVERT increased the alert level to Orange. Satellite imagery of Karymsky showed a narrow ash-and-gas plume at a height of ~ 3.5 km altitude on 30 June. Based on interpretations of seismic data, ash-and-gas plumes may have reached 3 km above the crater.

The Tokyo VAAC posted four messages on Karymsky during the 90 days prior to 8 August 2005; in each, ash was not identifiable from satellite. The earliest, 18 May was similar to the last one, on 23 June. Both noted a reported plume to FL100 ('flight level 100' signifies 10,000 feet; 3.05 km altitude). Reports on 22 and 24 May both noted ash to FL 120 (3.65 km altitude).

Information Contacts: KVERT (see Shiveluch); Tokyo Volcanic Ash Advisory Center (VAAC), Japan Meteorological Agency, Tokyo Aviation Weather Service Center, Haneda Airport 3-3-1, Ota-ku, Tokyo 144-0041, Japan (URL: http://www.jma.go.jp/JMA_HP/jma/jma-eng/jma-center/vaac/; Email: vaac@eqvol.kishou.go.jp).

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11/2005 (BGVN 30:11) Explosions continued during December 2004-June 2005

From December 2004 to June 2005 frequent explosions and plumes were detected at Karymsky (BGVN 30:06). In June 2005, the alert level was briefly lowered from Orange to Yellow because of a decrease in seismic and volcanic activity, but it was raised to Orange again on 23 June because of ash and gas plumes which rose to 3 km above the crater.

Karymsky remained at Concern Color Code Orange and seismicity remained above background levels throughout August-December 2005.

Throughout July 2005 ash-and-gas plumes frequently may have risen to 1-3 km above the crater. During 8-15 July, 450-600 shallow earthquakes occurred daily. On 11 July, an ash-and-gas plume extended about 11 km SE. During 15-22 July, 350-700 shallow earthquakes occurred daily. On 22 July, a weak thermal anomaly and a short E-drifting ash-and-gas plume were visible on satellite imagery.

Seismic activity during August indicated frequent possible ash-and-gas plumes up to 4 km altitude. A MODIS satellite thermal anomaly was registered on 2 August. On 22 August, three ash plumes reached heights around 3-4 km altitude and extended ~ 130 km E. An ash plume was visible at an altitude of ~ 5.8 km on 27 August.

Small ash and gas plumes continued to be emitted in September. A thermal anomaly was visible at the volcano on satellite imagery on 15 September.

Visual observations on 17 October revealed that the lava dome in the volcano's crater had been partially destroyed. Based on seismic data, three ash-and-gas plumes may have risen to 2.5-4 km altitude during 14-16 October. Five ash-and-gas plumes may have reached heights of 2.5-3.5 km altitude on several days during the last week of October 2005. A thermal anomaly at the volcano was visible on satellite imagery.

The lava dome inside the volcano's crater continued to grow during November 2005. Based on seismic data, three gas plumes containing some ash possibly rose 3-3.8 km altitude during 29-31 October and 1 November. Ash plumes were visible on satellite imagery extending NE on 31 October and 2 November. During 4-11 November five gas-and-steam plumes with some ash may have reached heights of 3-3.5 km altitude.

No seismic data were available after 10 November. A thermal anomaly was visible at the volcano on 15 and 17 November. According to seismic data, many weak shallow earthquakes and possible gas-steam plumes with some amount of ash up to 2.5 km altitude were registered on 20-23 November. A thermal anomaly was noted over the volcano during the last week of November and the first week of December. According to satellite data from Russia and USA, ash clouds moving to the SE from the volcano were noted on 6-7 December.

After 3 December the availability of seismic data became very erratic. A thermal anomaly was registered on 9-11 December and 14-15 December. According to satellite data, ash plumes and clouds were noted on 9 and on 10 December, moving SW and SE, and SE and E, respectively.

During the third week of December, many weak shallow earthquakes and possibly ten ash plumes up to 3.6 km altitude were registered. According to Kamchatka Volcanic Eruptions Response Team (KVERT) volcanologists who work near Karymsky, ash explosions rose up to 2.5-3 km altitude on 17-21 December 2005, and extended WSW and ENE. A thermal anomaly was registered over the volcano on 15-21 December. Seismicity indicated that ash explosions from the summit crater continued.

Many weak shallow earthquakes were registered during the last week of December. Ash plumes rose up to 2.5-4 km altitude on 24 December and 26-27 December and extended mainly E and SE from the volcano, and occasionally SW. According to KVERT volcanologists, a new cone approximately 60-80 m in diameter was formed at the summit of Karymsky volcano. A small lava dome 20-30 m in diameter was seen in the cone's crater. According to satellite data from the USA and Russia, a thermal anomaly was registered over the volcano all week.

Information Contacts: Olga Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA; Tokyo Volcanic Ash Advisory Center (VAAC) (URL: http://www.jma.go.jp/JMA_HP/jma/jma-eng/jma-center/vaac/; Email: vaac@eqvol.kishou.go.jp).

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04/2006 (BGVN 31:04) During April 2006, emerging ash plumes remained visible for up to 145 km

Karymsky was last reported on in BGVN 30:11. After frequent explosions from December 2004 to June 2005 (BGVN 30:06) a brief decrease in seismic and volcanic activity took place but this ended in late June when ash and gas plumes rose to 3 km above the crater. Seismicity remained above background levels throughout August-December 2005. During this period, ash and gas plumes and thermal anomalies were observed at the volcano.

Seismic activity indicated that ash explosions from the summit crater of Karymsky continued during 14-20 January 2006. Ash plumes extending 6-9 km S from the volcano were observed on 12 January and a thermal anomaly over the dome was observed during 13-15 January. According to seismic data, two possible ash plumes rose to 3.0-3.4 km altitude on 14-15 January.

According to reports from pilots of local airlines, ash emissions from Karymsky rose to 4-5 km altitude during 30-31 January. The ash plumes extended 13-29 km to the SW and SE, respectively. A thermal anomaly was visible at the lava dome during 27 January to 3 February, except when the volcano was obscured by clouds on 28 January. KVERT warned that activity from the volcano could affect nearby low-flying aircraft.

Strombolian activity continued through April 2006. During 10 February to 10 March, a large thermal anomaly was visible at the crater and numerous ash plumes were visible on satellite imagery extending as far as 140 km. On 9 March, a pilot reported an ash plume at a height of ~ 3 km altitude.

During 17-24 March, several ash plumes were visible on satellite imagery at a height of ~ 4 km altitude and extending SE and E. A thermal anomaly was seen at the volcano during periods of visibility. About 40-450 small earthquakes occurred daily.

During 7-14 April satellite imagery showed ash plumes extending ~ 40-145 km E and SE of the volcano, and a large thermal anomaly at the crater. Karymsky remained at Concern Color Code Orange from January to April 2006.

Information Contacts: Olga Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA; Tokyo Volcanic Ash Advisory Center (VAAC) (URL: http://www.jma.go.jp/JMA_HP/jma/jma-eng/jma-center/vaac/; Email: vaac@eqvol.kishou.go.jp).

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07/2006 (BGVN 31:07) Ash plumes reaching 5 km; ongoing eruptions through at least mid-2006

During April, May and June 2006, intermittent eruptive activity at Karymsky continued. Pilots had previously reported ash emissions from Karymsky rising to 3-5 km altitude during January to April 2006, during which time Karymsky remained at Concern Color Code Orange (BGVN 31:04). The same color code stayed in effect through August 2006.

Based on interpretations of April-June 2006 seismic data, ash plumes rose to altitudes of between 3 and 8 km. Satellite imagery showed a large thermal anomaly at the volcano's crater from January to August 2006, and numerous ash plumes and deposits extended 10-200 km SE and E of the volcano.

During 10-16 June 2006, 400-600 shallow earthquakes occurred daily. Ash plumes up to 5 km altitude traveling SE were observed by pilots. On 19 June, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured a false-color image of an ash plume from Karymsky (figure 12). During 21-27 June 200-700 shallow earthquakes occurred daily; during 23-30 June, 100-350 shallow earthquakes occurred daily.

According to the Tokyo VAAC, the Kamchatkan Experimental and Methodical Seismological Department (KEMSD) reported that during July 2006 ash plumes reached altitudes between 3 and 7 km. Approximately 100-350 shallow earthquakes occurred daily during 29 June to 3 July, and increased to 1,000 per day during 4-5 July.

Activity at Karymsky continued during 8-14 July, with 250-1000 shallow earthquakes occurring daily. Based on interpretations of seismic data, ash plumes reached altitudes of 5 km.

During August 2006, 100-300 shallow earthquakes occurred daily. Based on interpretations of seismic data, ash plumes reached altitudes of 3-3.7 km.

Information Contacts: Olga Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA; Tokyo Volcanic Ash Advisory Center (VAAC) (URL: http://www.jma.go.jp/JMA_HP/jma/jma-eng/jma-center/vaac/; Email: vaac@eqvol.kishou.go.jp).

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11/2006 (BGVN 31:11) Moderate ash explosions and continued dome growth

During late 2006 and into January 2007, ash explosions occurred from the summit crater at Karymsky, continuation of activity observed since the beginning of January 2006 (BGVN 31:04 and 31:07). This report covers activity during August 2006 to early January 2007.

The Kamchatka Volcanic Eruptions Response Team (KVERT) maintained the level of Concern Color Code at orange during the period of reporting, except for the temporary change to yellow during 8-15 September. Throughout this period the dome was a consistent source of thermal anomalies.

Ash plumes reached to ~ 3.0-3.7 km altitude throughout August 2006. Seismicity rose, with a maximum of 500 local shallow earthquakes per day the week of 18 August, and then lowered to 30-70 earthquakes per day the last week of August. Spasmodic tremor registered on 1-12 and 17 August. On 6 August an ash plume extending ~ 10-73 km E and SE was depicted on satellite data. Volcanic plume information sometimes stems from the Airport Meteorological Center (AMC) in Yelizovo (a town 40 km NE of the S-coast town of Petropavlovsk-Kamchatsky; the latter is the Peninsula's capital, largest city, and features both a major airport and a marine port). The AMC reported that on 16 August, pilots saw a Karymsky ash plume at ~ 6.5 km altitude that extended NE.

During September 2006, local shallow earthquakes occurred ~ 30-250 times per day. A satellite image for 12 September showed an ash plume extending ~ 140 km SE. On 10 September volcanologists observed from visual data an ash explosion of ~ [2.3 km] altitude. Other possible ash explosions were thought to occur toward the end of September 2006, reaching heights of ~ 2.5-4.5 km altitude.

Local seismicity peaked the last week of October with a maximum of 550 weak shallow earthquakes per day, but levels declined through November 2006. Possible ash explosions rising ~ 2.5-5.0 km altitude prevailed the month of October and during 10-11 and 18-19 November. On 25 October staff of the Institute of Volcanology and Seismology (IVS) observed a series of ash bursts up to ~ 2.0 km above the summit with ash plumes that extended ~ 100 km E. On days of sufficient visibility during October and November 2006, ash plumes often extended ~ 29-200 km NE, ~ 20-220 km SE, and ~ 55-137 km E (figure 13). On 28 October observers noted an ash cloud extending to 70 km NE of Karymsky.

There were no seismic data the last week of November to the third week December 2006, but satellite data enabled surveillance. Figure 14 shows a 19 December image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on the Terra satellite.

During the week of 29 December and the first week in January 2007 there were multiple weak local shallow earthquakes. They occurred at a rate of 100-130 per day during the week of 29 December. On 29 December and 1-3 January tremor was also registered.

According to visual information from pilots of international air flights (reported by AMC, Yelizovo), on 2 December an ash plume rose up ~ 6.9 km altitude and extended E. At 0200 on 22 December an ash plume rose up to ~ 7.0 km altitude and extended E. A number of ash plumes extending 9 to 240 km E were observed during December. At the end of December 2006 and into early January 2007, a possible lava flow was observed on a flank of the volcano.

Information Contacts: Olga A. Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia (Email: girina@kscnet.ru), GS RAS (Russia), and the Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA; Jesse Allen, National Aeronautics and Space Administration Earth Observatory (URL: http://earthobservatory.nasa.gov/NaturalHazards).

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07/2008 (BGVN 33:07) Ongoing explosions that began in 1996 continued through September 2008

Karymsky stratovolcano, one of most active of the Eastern Volcanic Zone of the Kamchatka arc, began an eruptive cycle in January 1996 lasting through at least September 2008. This report covers activity from June 2008 to September 2008 (figure 15).

During June-September, there were alternating periods of strengthening and weakening activity. Ash plumes were emitted and hot avalanches repeatedly descended the flanks. Seismic events usually had local magnitudes (ML) less than 2.5. Local shallow earthquakes were associated with crater explosions. Satellite data registered thermal anomalies usually on the crater, suggesting the eruption of hot magmatic material such as a lava flow or fragmental avalanches. An increase in the anomaly to 4-7 pixels usually accompanied a lava flow. Code Orange days during the reporting period occurred on the following days (table 4).

Table 4. Thermal anomalies at Karymsky from NOAA-15 satellite images and visual observations for the interval from June to September 2008. Courtesy of Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS).

    Date           Thermal     Comments
                   anomaly
                   (pixels)

    27 Aug 2008       -        Local shallow earthquakes; ash plume 2.9-3.2 km altitude
    28 Aug 2008       4        Local shallow earthquakes; ash plume 2.6-3.0 km altitude
    29 Aug 2008       4        Local shallow earthquakes; ash plume 3.0-3.8 km altitude
    31 Aug 2008       1        Local shallow earthquakes; ash plume 3.0 km altitude
    01 Sep 2008       -        Local shallow earthquakes; ash plume 3.3 km altitude
    08 Sep 2008       -        Local shallow earthquakes; ash plumes reaching 2.2-3.2 km altitude
    13 Sep 2008       2        Local shallow earthquakes
    14 Sep 2008       2        Local shallow earthquakes; ash plume 2.9 km altitude

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Aleksey Ozerov, Institute of Volcanology and Seismology, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia (Email: kvert@kscnet.ru, URL: http://www.kscnet.ru/ivs/; http://www.ozerov.ru); Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS), Sergey Senukov, Russia (Email: ssl@emsd.iks.ru; URL: http://wwwsat.emsd.ru/alarm.html; http://wwwsat.emsd.ru/~ ssl/monitoring/main.htm).

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12/2008 (BGVN 33:12) Ash plumes during 2007-January 2009, one over 450 km long

This report summarizes activity at Karymsky from February 2007 to 23 January 2009, with the exclusion of June-September 2008 (figure 16), when activity was variable (BGVN 33:07). During the reporting interval the Level of Concern Color Code remained at Orange. Overall activity during 2007 was also variable, but increased during July-December 2007 (figure 17).

During February to April 2007, activity was characterized by constant ash explosions and steam-and-gas emissions. Thermal anomalies were detected, and plumes rose to altitudes of 2.5-5.0 km before drifting NW, N, NE, E, and SE (figure 18).

During May 2007 the volcano quieted; activity was characterized by low steam-and-gas emissions. There was increased seismicity in July-October 2007, with a daily high of 900 events in mid-July. During 21-27 September ash plumes extended over 450 km E, and on 5, 7, and 8 October ash plumes that rose to 30 km altitude drifted E and NE. Activity decreased after November, but steaming was evident (figure 19).

During March-April 2008 explosive activity again increased. On 15-16 March an ash plume drifted 40 km to the SE, and ash deposits were noted 15-20 km to the NE and ESE of the summit. On 3 April ash deposits were noted in areas about 20 km to the E, 70 km to the SW, and 45-50 km to the S. On 8 April an ash plume drifted 70-80 km ESE.

On 11 October 2008 an ash plume rose to an altitude of 3.4 km, and on 13 October a 5-km-wide ash plume drifted 32 km NNE. On 2 November an ash plume rose to an altitude of 4 km. On 10 November an ash plume drifted 38 km E, and 28 km ENE. On 15 November an ash plume extended 28 km to the E. On 8 December ash plumes rose to altitudes of 2 km and ash deposits on the E flank were more than 5 km long. On 16 December an ash plume extended 240 km to the SE and ESE. During 21-23 December ash plumes extended about 80 km to the E. Ash deposits were noted on 21 December; the deposits extended 26 km SE and 9 km NE.

As late as 8 and 12 January 2009, gas-and-steam plumes extended about 25 km to the SE and NE. The Tokyo VAAC reported that on 16 January an ash plume rose to an altitude of 3.7 km and drifted SE. Analysis of satellite imagery revealed a thermal anomaly in the crater during 18-19 and 21 January 2009.

Reference. Senyukov, S.L., Droznina, S.Y., Nuzhdina, I.N., Garbuzova, V.T., Kozhevnikova, T.Y., Toloknova, S.L., and Sobolevskaya, O.V., 2008, Monitoring of active Kamchatkan volcanoes using remote methods in 2007: Conference proceedings, dedicated to the day of volcanologists, on 27-29 March, 2008, Petropavlovsk-Kamchatsky: IViS FED RAN, 329 p. (in Russian).

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanology and Seismology (IV&S) Far East Division, Russian Academy of Sciences (FED RAS), Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS), Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia (Email: kvert@kscnet.ru, URL: http://www.kscnet.ru/ivs; http://emsd.iks.ru/~ssl/monitoring/main.htm); Alexander Sokorenko, IV&S; Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/).

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08/2009 (BGVN 34:08) New 14 August explosion crater formed on S side of upper summit

This report covers 23 January to 9 September 2009, an interval with both thermal anomalies and ash plumes. A new explosion crater formed on the upper S flank on 14 August 2009. Many thermal anomalies were detected during 21 February to 1 March 2009 (figure 20).

During March 2009, Karymsky plumes were abundant (table 5). They were extending up to 200 km long on the 12th and 16th-17th. During 25 April and 19 May activity decreased although gas-and-steam emissions continued (figure 21).

Table 5. Summary of plumes observed at Karymsky during 21 February to 4 June 2009. Data compiled from listed sources.

    2009         Ash plume                  Source

    21 Feb       150 km NE                  KEMSD; Tokyo VAAC 
    04 Mar       120 km SE                  KEMSD; Tokyo VAAC 
    05 Mar        75 km ENE; 64 km SE       NOAA 16; NOAA 17
    06 Mar       160 km E; 115 km E         NOAA 17; NOAA 16
    07 Mar       115 km SE                  NOAA 16
    08 Mar        50 km SW                  NOAA 16; NOAA 17
    09 Mar        50 km SW; 30 km E         NOAA 17
    12 Mar       200 km E                   KEMSD; Tokyo VAAC 
    13 Mar       130 km E                   NOAA 17; NOAA 16
    16-17 Mar    200 km E                   KEMSD; Tokyo VAAC 
    26 Mar       ash deposits to 30 km S    KEMSD; Tokyo VAAC 
    04 Jun        30 km SE                  KEMSD; Tokyo VAAC 

Volcanologists reported from a camp on Karymsky lake that at 1600 on 14 August 2009 they noticed a series of small ash emissions. They saw plumes rising to ~ 2.5 km altitude. As a result of the eruption, a crater formed on the volcano's upper S slope. The new explosion crater was round and deep, with a diameter of 70 m. At the time of the call the crater was still steaming to a height of 200 m above the crater (figure 22).

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far East Division, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (Email: kvert@kscnet.ru, URL: http://www.kscnet.ru/ivs/); Kamchatka Branch of the Geophysical Service, Russian Academy of Sciences (KB GS RAS), Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://emsd.iks.ru/~ssl/monitoring/main.htm), Sergei Chirkov and Alexander Manevich, IV&S FED RAS; Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/).

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05/2012 (BGVN 37:05) Many ash plumes to 4 km during September 2009-September 2010

This report on Karymsky covers September 2009 to September 2010, an interval with consistent thermal anomalies, seismic activity, and ash plumes. This report was written primarily by Jason Kaiser as part of a graduate student writing assignment in a volcanology class at Oregon State University under the guidance of professor Shan de Silva.

Activity during September 2009-September 2010 was similar to reported activity during January to September 2009 (BGVN 34:08), characterized by nearly consistent thermal anomalies (when cloud cover allowed satellite observations) and above-background seismic activity (figure 23). Ash plume altitudes averaged between 3.5 and 4 km, occurring at least once a week for large portions of this time period. These plumes typically drifted between 100 and 200 km E over the N Pacific Ocean. Ash plume altitudes reported by Kamchatka Volcanic Eruptions Response Team (KVERT) were mostly based on seismic data interpretation, rather than direct observation. Information on thermal anomalies, seismic activity, and ash plume dispersal was reported by KVERT and Tokyo Volcanic Ash Advisory Center (VAAC); first-hand observations by scientists in the area were rare. Plume altitudes and maximum dispersals during the reporting period are shown in figure 24.

After being lowered to Green in August 2009, the Aviation Color Code was again raised to Yellow on 22 September 2009, then to Orange on 23 September, both times because of increased seismicity and possible ash explosions. Scientists flying near Karymsky in a helicopter on 22 September observed ash plumes that rose to altitudes of 1.7 km and drifted E.

The Aviation Color Code remained at Orange for the rest of 2009. Thermal anomalies and above-background seismicity were common, occurring consistently each week during October-November 2009. Few direct observations were made, but scientists did note fumarolic activity on 1 October and a small ash plume reaching 3.5 km altitude and drifting SSE on 7 October. On 12 October, volcanologists doing fieldwork in the area observed and photographed an ash plume that later rose to an altitude of 3.5 km (figure 25).

KVERT reported that ash deposits observed in satellite imagery extended 45 km SE on 6 December. No seismic or thermal data were available for 8 December 2009, yet a new lava flow on the S flank was observed on that day. Based on information from Yelizovo Airport, the Tokyo VAAC reported that on 25 December an ash plume rose to an altitude of 6.7 km. That same day, KVERT noted three linear ash deposits in satellite imagery that extended nearly 10 km SE from the vent. Smaller gas-and-steam bursts were observed by scientists in the area three days later.

Thermal anomalies were observed in satellite imagery nearly every day during January-March 2010. Above background seismicity was also common during this period. Ash explosions were assumed to be consistent with the seismic activity during this time frame, and were weak during February. The Aviation Color Code remained at Orange for much of this period, but was lowered to Yellow at the end of February.

KVERT reported that seismicity increased on 25 March 2010. On 27 March an intense thermal anomaly over the volcano was apparent in satellite imagery and ash plumes were observed in the area of the volcano during 28-29 March, drifting 250 km SSE (the longest reaching ash plume during this reporting interval, table 6). The Aviation Color Code was again raised to Orange on 29 March.

Table 6. Reported characteristics of eruptive plumes at Karymsky during September 2009-September 2010. Included are plume-top altitude (kilometers above sea level, km a.s.l.), drift direction, and drift distance (when available). Data are courtesy of KVERT or Tokyo VAAC; ‘-’ indicates data not reported.

   Date         Plume altitude          Drift direction             Source
mm/dd/yyyy        (km a.s.l.)       (+ distance, if available)

9/22/2009              2                        -                   KVERT
9/23/2009             4.5                       E                   KVERT
10/7/2009             3.5                      SSE                  KVERT
10/9/2009              3                        -                   VAAC
10/12/2009            3.5                       -                   KVERT
10/20/2009            3.3                       -                   VAAC
10/23/2009            3.9                   120 km E                KVERT
10/24/2009            3.4                       -                   VAAC
10/25/2009            3.7                       -                   VAAC
10/31/2009            3.7                   180 km E                KVERT
11/5/2009             3.7                   180 km E                KVERT
11/8/2009              3                        -                   VAAC
11/10/2009            3.4                   190 km E                VAAC
11/14/2009            3.7                       E                   VAAC
11/17/2009             3                    130 km E                KVERT
11/23/2009             4                    120 km E                VAAC
11/25/2009            3.8                   120 km E                KVERT
12/25/2009            6.7                       SE                  VAAC
1/12/2010              3                    113 km SE               KVERT
1/15/2010              3                        -                   KVERT
3/12/2010             5.8                       -                   VAAC
3/26/2010             4.1                       -                   KVERT
3/29/2010             4.1                   250 km E                KVERT
4/17/2010              2                    130 km SE               KVERT
4/20/2010              3                        -                   KVERT
4/28/2010              3                        -                   KVERT
5/7/2010               2                        -                   KVERT
5/13/2010             4.6                       -                   KVERT
5/17/2010             2.5                    18 km NE               KVERT
5/25/2010             4.3                     SW, NW                KVERT
5/28/2010              3                     63 km S, W             KVERT
6/1/2010               4                     30 km S                KVERT
6/6/2010              2.5                       -                   KVERT
6/11/2010             6.1                   195 km E                VAAC
6/12/2010             5.2                       -                   KVERT
6/16/2010             3.9                    22 km E                KVERT
6/29/2010              7                        -                   VAAC
7/7/2010               2                     20 km S                KVERT
7/13/2010             2.7                       W                   VAAC
7/14/2010             3.3                       -                   KVERT
7/19/2010             1.5                       SW                  KVERT
7/23/2010              3                     85 km SE               KVERT
7/28/2010              2                     15 km SE               KVERT
7/30/2010              2                        -                   KVERT
8/13/2010             2.5                       -                   KVERT
8/16/2010              3                    100 km E                VAAC
8/20/2010             3.8                       -                   KVERT
8/27/2010             3.8                    23 km                  KVERT
9/3/2010              3.7                       -                   KVERT
9/10/2010             3.2                       -                   KVERT
9/15/2010             3.2                       -                   KVERT

Thermal anomalies and above-background seismicity were noted consistently throughout April 2010. KVERT reported ash plumes drifting 40-130 km SE on 17 and 21 April. Volcanologists working in the area on 20 and 21 April observed ash bearing gas-and-steam plumes that rose to an altitude of 3 km. Strombolian activity was occasionally observed at night (figure 26).

During May-August 2010 ash plumes were common, occurring fairly consistently each week, and sometimes confirmed by satellite imagery. Based on information from Yelizovo Airport and KVERT, Tokyo VAAC reported that ash plumes rose to an altitude of 4.3 km a.s.l. and drifted SW and W on 22 and 25 May. During 25 June-2 July seismicity at Karymsky was above background levels and suggested that possible ash plumes rose to altitudes up to 7 km a.s.l. Strong thermal anomalies were detected on 27 June. Ash plume altitudes over this period are plotted in figure 24a.

The Aviation Color Code remained at Orange through September 2010 due to consistent thermal and seismic anomalies. Seismic data suggested some intervals where ash plumes rose from the volcano almost daily. September ash plumes were repeatedly calculated or observed in satellite imagery to reach maximum altitudes of 4 km. Dispersal estimates were rare during September 2010 due to limited visibility, but were not reported to be greater than 100 km to the SSE (figure 24b, table 6).

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far East Division, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/); Kamchatka Branch of the Geophysical Service, Russian Academy of Sciences (KB GS RAS), Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://emsd.iks.ru/~ssl/monitoring/main.htm), Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/).

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