Tolbachik

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 55.83°N
  • 160.33°E

  • 3682 m
    12077 ft

  • 300240
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

21 August-27 August 2013

KVERT reported that the S fissure along the W side of Tolbachinsky Dol, a lava plateau on the SW side of Tolbachik, continued to produce very fluid lava flows during 16-22 August that traveled to the W, S, and E sides of the plateau. Cinder cones continued to grow along the S fissure and weak gas-and-steam plumes were observed. A thermal anomaly on the N part of Tolbachinsky Dol was visible daily in satellite imagery.

Seismic activity decreased during 22-24 August. Video images showed no incandescence from the N part of Tolbachinsky Dol, although a thermal anomaly continued to be detected in satellite images. On 27 August the Aviation Color Code was lowered to Yellow.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)



Index of Monthly Reports

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

09/1970 (CSLP 00-70) Lava in crater; scoria ejections

07/1975 (CSLP 51-75) Explosions from four flank vents of Plosky Tolbachik

08/1975 (CSLP 51-75) Ash and lava emission from new cone on the S slope of Plosky Tolbachik

04/1976 (SEAN 01:07) Eruption that began in July 1975 is continuing

05/1976 (SEAN 01:08) Eruption now almost a year old; possibly four new cones

01/1994 (BGVN 19:01) Seismic monitoring stations installed; activity at background levels

11/1994 (BGVN 19:11) Seismic station closed

02/1999 (BGVN 24:02) Gas-and-steam explosion; minor seismicity

12/2012 (BGVN 37:12) Seismicity precedes onset of dual fissure eruption in November 2012

08/2013 (BGVN 38:08) 2012-2013 Strombolian eruption produced lava flows 17-20 km long


Contents of Monthly Reports

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

All times are local (= UTC + 12 hours)

09/1970 (CSLP 00-70) Lava in crater; scoria ejections

Card 1018 (25 September 1970) Lava in crater; scoria ejections

The following cable was received [on] 25 September 1970. "Plosky Tolbachik: Lava appeared in crater; weak scoria outbursts few meters height."

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

07/1975 (CSLP 51-75) Explosions from four flank vents of Plosky Tolbachik

Card 2216 (08 July 1975) Explosions from four flank vents of Plosky Tolbachik

The eruption of Plosky Tolbachik volcano commenced from the flank craters on 6 July 1975 at 0045 GMT. Four explosion vents located 18 km from the main crater are active. The place and time of eruption were predicted by Dr. Tokarev according to the character of the seismic activity.

Information Contact: Y. Doubik, IVP.

08/1975 (CSLP 51-75) Ash and lava emission from new cone on the S slope of Plosky Tolbachik

Card 2245 (07 August 1975) Ash and lava emission from new cone on the S slope of Plosky Tolbachik

A volcanic cone 250 m high and 1,200 m in diameter has formed on the south slope of Plosky Tolbachik volcano. Violent activity was observed from 9 to 23 July, producing an ash column 8 km high and bomb outbursts up to 2,500 m. The ashfall area covers 200 km2, and the total of the ash and scoria amounts to 500 m3. On 30 July a lava outflow began issuing from a 1-km-long eruptive fissure on the southwest slope of the new volcanic cone. There is a danger of forest fires.

Information Contact: Y. Doubik, IVP.

04/1976 (SEAN 01:07) Eruption that began in July 1975 is continuing

The eruption of Plosky Tolbachik volcano, which started in July 1975, is continuing.

Information Contact: Y. Doubik, IVP.

05/1976 (SEAN 01:08) Eruption now almost a year old; possibly four new cones

Plosky Tolbachik has been in a state of eruption for almost a year. It was reported on 17 May that a new volcano was developing near there, and a group of IVP scientists is investigating the eruption. They stated that "this is one of the biggest and most interesting volcanic eruptions this century." Reportedly, a chain of new volcanoes was formed during the eruption, four of which are fairly large. "Streams of fire" have been active for nearly a year.

Information Contact: Y. Doubik, IVP.

01/1994 (BGVN 19:01) Seismic monitoring stations installed; activity at background levels

Seismic monitoring . . . by the KVERT began in late January 1994 when two stations were installed. Since then seismicity was considered to be at background levels. One earthquake was registered on 25 January. During the period from 28 January to 2 February, shallow volcanic earthquakes were registered at a rate of 5-13/day. The following week (3-8 February) there were 1-4 shallow earthquakes recorded each day.

Information Contacts: V. Kirianov, IVGG.

11/1994 (BGVN 19:11) Seismic station closed

[Following notice in early December that seismic stations at Shiveluch and Tolbachik had closed, on 22 December the following message was sent from the Alaska Volcano Observatory (AVO): "KVERT [Kamchatka Volcanic Eruptions Response Team] has informed AVO that, because of a long delay in promised funding from the Ministry of Transportation in Moscow, KVERT must suspend transmittal of information on volcanic activity in Kamchatka. The length of the suspension is unknown at this time.]

Information Contacts: V. Kirianov, IVGG; T. Miller, AVO.

02/1999 (BGVN 24:02) Gas-and-steam explosion; minor seismicity

On 18 February, a gas-and-steam explosion generated a plume to 600 m above the volcano. Small (magnitudes near zero) shallow earthquakes were registered under the volcano and continued through the month, coincident with M 1.5 events at 15-30 km depth. No further unusual seismicity was reported as of mid-March.

The massive Tolbachik basaltic volcano is located at the southern end of the dominantly andesitic Kliuchevskaya volcano group. The Tolbachik massif is composed of two overlapping, but morphologically dissimilar volcanoes. The flat-topped Plosky Tolbachik shield volcano with its nested Holocene Hawaiian-type calderas up to 3 km in diameter is located east of the older and higher sharp-topped Ostry Tolbachik stratovolcano. Lengthy rift zones extending NE and SSW of the volcano have erupted voluminous basaltic lava flows during the Holocene, with activity during the past two thousand years being confined to the narrow axial zone of the rifts. The last eruptive activity, in 1975-76, vented from both the summit and SSW-flank fissures; it was the largest historical basaltic eruption in Kamchatka.

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.

12/2012 (BGVN 37:12) Seismicity precedes onset of dual fissure eruption in November 2012

Nearly 36 years after its last eruption, the largest basaltic eruption in Kamchatka during historic times (1975/76 eruptions; CSLP 51-75; SEAN 01:07, 01:08), Tolbachik (figure 1) began erupting again on 27 November 2012 following almost three weeks of episodic volcanic tremor. The eruption emerged as two fissures along the W side of Tolbachinsky Dol (a lava plateau along the SW flank of Tolbachik), in the same area as the northern vents of the 1975/76 eruptions. The eruption produced both effusive lava flows and explosions that generated low-level ash-bearing plumes.

Figure 1. Shuttle Radar Topography Mission (SRTM) colored elevation and shaded relief map highlighting the location of Tolbachik at the S end of the Kliuchevskoi (Kliuchevskaya) volcanic group, Kamchatka Peninsula, Russia (inset shows regional setting, with the Kamchatka peninsula highlighted in dark gray at the top right, and the location of the Kliuchevskoi volcanic group indicated by the star). Tolbachik comprises the flat-topped Plosky Tolbachik shield volcano (and its nested calderas) to the E and the sharp-topped Ostry Tolbachik stratovolcano to the W. SRTM map modified from NASA Jet Propulsion Laboratory; inset regional map modified from Wikipedia.

This report mainly summarizes Kamchatkan Volcanic Eruption Response Team (KVERT) daily and weekly reports and information releases concerning the ongoing (as of early February 2013) Tolbachik fissure eruption.

Seismicity preceding 27 November 2012 eruption. Episodic tremor was recorded at Tolbachik during 7-10, 18, and 26 November 2012; KVERT noted a distinct difference between these episodes of tremor and discrete events that had occurred over “many years” prior. Shallow volcanic earthquakes began on 26 November, increasing in number to ~267 through 27 November. The Aviation Color Code was raised from Green to Yellow (on a scale increasing from Green-Yellow-Orange-Red) on 27 November. In a daily report discussing activity on 27 November, KVERT reported that shallow events, possibly indicating ash explosions, had occurred during 1715-2000. The Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS) reported a strong seismic event at 1752 that day. Informed by KB GS RAS, the Tokyo Volcanic Ash Advisory Center (VAAC) posted a volcanic ash advisory at 1837 (table 1). The ash explosions prompted KVERT to raise the Aviation Color Code to Orange. Continuos tremor occurred for the rest of the day, indicating possible lava flows.

Table 1. Summary of Tokyo VAAC volcanic ash (VA) advisories for Tolbachik during November 2012-January 2013. Plume heights are reported in km above sea level (a.s.l.); ‘-’ indicates data not reported. Note that the fissures are at approximately 1,600-1,700 m elevation, and not at the summit (3,682 m elevation), thus complicating plume height estimates. Yelizovo Airport is indicated as a data source by its airport code, UHPP. All times are local (UTC - 12 hours). Courtesy of Tokyo VAAC.

  Date      Time    Plume height    Drift        Remarks (data source)
                     (km a.s.l.)    Direction    

2012
  27 Nov    1837        6.1            -         Eruption reported at 1715 (KB GS RAS)
  27 Nov    2313       10.05          NNW        Eruption (KB GS RAS)
  29 Nov    1003        3.95           N         VA reported (UHPP)
  29 Nov    1500        3.65           SE        VA reported (KVERT)
  29 Nov    1746        3.95           SE        Continuing emissions (satellite imagery)
  29 Nov    2355        3.95           SE        Continuing emissions (satellite imagery)
  30 Nov    0600        3.95           N         Continuing emissions (satellite imagery)
  30 Nov    1152         -             -         VA dissipated on imagery (satellite imagery)
  30 Nov    1634       <6.1            N         VA reported (UHPP)
  03 Dec    2138        4.25           NW        VA reported (UHPP)
  05 Dec    1221        4.25           SE        VA reported (KVERT)
  07 Dec    1431        4.25           SW        VA reported (KVERT)
  13 Dec    1139        3.05           NE        VA reported (KVERT)
  13 Dec    1232        4.55           E         VA reported (UHPP)
  14 Dec    1209        3.05           NE        VA reported (KVERT)
  27 Dec    1126        5.2            SE        VA reported (UHPP)

2013
  07 Jan    1145        3.65           NE        VA reported (KVERT)
  07 Jan    1202        4.25           NE        VA reported (KVERT)

Observations reveal two fissure vents. By the early morning of 28 November 2012, observers in Kozyrevsk (~40 km NW) and Lazo (~50 km SW) had reported periodic incandescence from Tolbachik during the night. Later that morning, observers in the same locations reported ash explosions and lava flows in the area of the northern vents of the 1975/76 eruptions, along the W side of Tolbachinsky Dol.

The first available photograph of the eruption showed that lava was issuing through two fissures (figure 2). Ashfall 4-cm-deep was reported in Krasny Yar (~60 km NNW) by midday on 28 November (figure 3). According to a KVERT information release, the Aviation Color Code was raised to Red for a brief period on 29 November, but this was not reflected in the daily reports; the Aviation Color Code remained Orange for the remainder of the reporting interval.

Figure 2. The first available photograph of the Tolbachik dual fissure eruption that began on 27 November 2012. Fire fountaining through two fissure vents are seen generating ash plumes that reached ~3 km above sea level on 28 November 2012. Courtesy of Dmitry Melnikov (IVS FED RAS) and KVERT.
Figure 3. Ashfall from Tolbachik was reported in Krasny Yar (~60 km NNW). Two deposits are distinguishable, separated by fresh snowfall; lens cap for scale. Courtesy of Y. Demyanchuk (IVS FED RAS) and KVERT.

KVERT reported on 28 November that the N and S fissures were located 4-5 km and 6-7 km S of Plosky Tolbachik, respectively. Plosky Tolbachik is a shield volcano with nested summit calderas that makes up the E half of Tolbachik; the W portion of Tolbachik is the sharply-peaked Ostry Tolbachik stratovolcano (figures 1 and 4). At that time, Strombolian activity (figure 5) was observed at 4-5 vents in the N fissure and 2-3 vents in the S fissure; the very fluid lavas (figure 6) were flowing, often in ‘lava rivers’, to the W side of Tolbachinsky Dol (figure 7), and KVERT noted a large thermal anomaly over the N part of Tolbachinsky Dol (figure 8). Observers reported booming noises and vibrating windowpanes.

Figure 4. Tolbachik viewed from the NNE on 13 December 2012, showing Plosky Tolbachik, the shield volcano, and its large, nested summit calderas on the left (E) and Ostry Tolbachik, the sharply peaked stratovolcano on the right (W). An E-drifting plume is seen rising from the fissure eruption on Tolbachinsky Dol to the S (in the background). Courtesy of Y. Demyanchuk (IVS FEB RAS) and KVERT.
Figure 5. Strombolian activity during the eruption from the S fissure of Tolbachinsky Dol on 29 November 2012. Courtesy of S. Samoilenko and A. Sokorenko (IVS FEB RAS) and KVERT.
Figure 6. Photographs highlighting the very fluid nature of lavas effused from the fissure eruption of Tolbachinsky Dol. (a) Fluid lavas from the S fissure of Tolbachinsky Dol flowing in a ‘lava river’ on 6 December 2012. A dog is in the foreground for scale. Courtesy of V. Yaschuk (KB GS RAS) and KVERT. (b) A ‘lava river’, presumably effused from the S fissure, flowing around a ‘lava island’ on 23 January 2013. Courtesy of Y. Demyanchuk (IVS FEB RAS) and KVERT.
Figure 7. A false color infrared satellite image showing lava flowing W from the fissure eruption of Tolbachinsky Dol; snow appears green in this image. The fissure vents are hidden behind the plume in the N part of the image. To the S of the lava flow are cinder cones from the 1975/76 eruption of Tolbachik. The image was collected on 1 December 2012 by the Advanced Land Imager on the Earth Observing-1 Satellite; courtesy of NASA Earth Observatory.
Figure 8. A MODVOLC thermal alert image for 29 November 2012 showing a large thermal anomaly over the N portion of Tolbachinsky Dol, resulting from the eruption of lava through two fissure vents. This image is a combination of multiple pixel alerts registered at 7 different times during the same day. Courtesy of the Hawai`i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System.

On 29 November, seismicity declined, and KVERT characterized the eruption as effusive; renewed seismicity occurred the next day, and a gas-and-steam plume with small amounts of ash rising to ~3 km was reported. Lava flows from the N fissure destroyed two scientific base camps located ~10 km from Tolbachik.

Cinder cones grow on S fissure; new fumarole. A KVERT weekly report issued on 6 December 2012 noted that cinder cones were growing on the S fissure, and that lava effused from the S fissure had flowed up to 20 km away by 7 December. A fumarole was observed at the bottom of the Plosky Tolbachik caldera on 8 December (figure 9); this was the first fumarole observed in the caldera in ~30 years. On 9 December KVERT daily reports began stating that the effusion of lava was continuing from the S fissure, no longer mentioning the N fissure.

Figure 9. A new fumarole that was observed in the Plosky Tolbachik caldera on 8 December 2012. KVERT reported that this is the first fumarole in the caldera in ~30 years. Courtesy of O. Evdokimova (IVS FEB RAS) and KVERT.

By the end of December, KVERT reported that five cinder cones were growing on the S fissure (e.g. figure 10); by 10 January 2013, however, KVERT reported only four cinder cones on the S fissure.

Figure 10. Strombolian activity within a cinder cone on the S fissure of Tolbachinsky Dol on 27 December 2012. The strombolian activity is feeding a lava river, flowing to the left. Courtesy of Y. Demyanchuk (IVS FEB RAS) and KVERT.

As of early February 2013, the eruption continued to produce very fluid lava flows, four growing cinder cones, gas-and-steam plumes with variable ash contents that often reached ~4 km a.s.l. and drifted in various directions, and daily thermal alerts above Tolbachinsky Dol. Two examples of eruptive products from the eruption are shown in figure 11.

Figure 11. Examples of eruptive products from the fissure eruption of Tolbachik that began on 27 November 2012 (ongoing as of early February 2013). (a) Vesicular lava sample (of unspecified dimensions and source location) photographed on 15 December 2012, displaying a very fluidal texture. (b) A volcanic bread-crust bomb photographed in situ (unspecified dimensions and source location) on 24 January 2013. Courtesy of Y. Demyanchuk (IVS FEB RAS) and KVERT.

Information Contacts: Kamchatkan Volcanic Eruption 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://ds.data.jma.go.jp/svd/vaac/data/); Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS), Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Yelizovo Airport (UHPP), Petropavlovsk-Kamchatsky, Kamchatka Krai, Russia; NASA Earth Observatory, NASA Goddard Space Flight Center (URL: http://earthobservatory.nasa.gov/); NASA Jet Propulsion Laboratory, California Institute of Technology (URL: http://www.jpl.nasa.gov/); Wikipedia (URL: http://www.wikipedia.org/).

08/2013 (BGVN 38:08) 2012-2013 Strombolian eruption produced lava flows 17-20 km long

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Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2012 Nov 27 2013 Aug 22 (?) Confirmed 4 Historical Observations Tolbachinsky Dol
1975 Jun 28 1976 Dec 10 Confirmed 4 Historical Observations South flank (18 & 28 km from summit)
[ 1973 Oct ] [ 1974 Dec ] Uncertain 1  
1970 Sep 1970 Dec 1 ± 30 days Confirmed 2 Historical Observations
1970 Jan 1970 Apr Confirmed 1 Historical Observations
1968 1969 Confirmed 1 Historical Observations
1967 Oct 1967 Nov Confirmed 2 Historical Observations
1967 Mar 1967 May Confirmed 2 Historical Observations
1966 Apr 15 ± 45 days Unknown Confirmed 2 Historical Observations
1965 Unknown Confirmed 1 Historical Observations
1964 Mar 1964 Apr 24 (in or after) Confirmed 2 Historical Observations
1962 Aug 1963 Confirmed 1 Historical Observations
1961 Mar 24 1962 Feb 16 (in or after) Confirmed 2 Historical Observations
1959 1960 Confirmed 2 Historical Observations
1958 Jul 13 (in or before) Unknown Confirmed 2 Historical Observations
1956 Sep 28 1957 Nov 28 Confirmed 2 Historical Observations
1955 Oct 6 1955 Dec 8 Confirmed 2 Historical Observations
1955 Jan 7 1955 Feb 9 Confirmed 2 Historical Observations
1954 Feb 21 1954 Jun 13 Confirmed 2 Historical Observations
1947 Jan Unknown Confirmed 2 Historical Observations
1940 Nov 1941 Jul 15 ± 45 days Confirmed 3 Historical Observations Summit, SW flank (1950 m)
1940 Feb 1940 Apr Confirmed 2 Historical Observations
1939 Sep 25 1939 Sep 27 Confirmed 2 Historical Observations
1936 Aug 13 (in or before) 1937 Mar 2 Confirmed 2 Historical Observations
1931 Mar 4 1932 Confirmed 2 Historical Observations
1904 Unknown Confirmed 2 Historical Observations
1793 Unknown Confirmed 2 Historical Observations
1790 Unknown Confirmed 2 Historical Observations
1789 Unknown Confirmed 2 Historical Observations
1788 Unknown Confirmed 2 Historical Observations
1769 Feb 15 ± 45 days 1769 Oct 15 ± 45 days Confirmed 2 Historical Observations
1740 Dec Unknown Confirmed 2 Historical Observations
1739 Feb 1 ± 30 days Unknown Confirmed 2 Historical Observations
[ 1699 ± 1 years ] [ Unknown ] Uncertain 2  
1550 (?) Unknown Confirmed 2 Tephrochronology SW flank (Zvezda)
1050 (?) Unknown Confirmed 3 Tephrochronology SW flank (Visokaya, Treschina)
1000 (?) Unknown Confirmed 4 Tephrochronology SW flank (Kleshnya, Rastaschenny)
0950 (?) Unknown Confirmed 4 Tephrochronology SW flank (Alaid)
0900 (?) Unknown Confirmed 4 Tephrochronology SW flank (Peschanie Gorky)
0550 (?) Unknown Confirmed 3 Tephrochronology SW flank (Kamenistaya)
0450 (?) Unknown Confirmed 3 Tephrochronology SW flank (Dvoinoy, Nedostupny, Dalny)
0400 (?) Unknown Confirmed 4 Tephrochronology SW flank (Pelmen, Lagerny)
0350 (?) Unknown Confirmed   Tephrochronology SW flank (Zasipannie)
0250 (?) Unknown Confirmed   Tephrochronology SW flank (Poteryanny, Yupiter)
0150 (?) Unknown Confirmed   Tephrochronology SW flank (Zapretny)
0050 (?) Unknown Confirmed 4 Tephrochronology SW flank (Mt. 1004, Pra-Visokaya)
0100 BCE (?) Unknown Confirmed   Tephrochronology SW flank (Sosed, Malenky)
0200 BCE (?) Unknown Confirmed   Tephrochronology SW flank (Kust)
0700 BCE (?) Unknown Confirmed   Tephrochronology SW flank (Buraya)
0750 BCE (?) Unknown Confirmed   Tephrochronology SW flank (Tsepochka, Malishi)
0800 BCE (?) Unknown Confirmed   Tephrochronology SW flank (Serga, Starichky)
1650 BCE (?) Unknown Confirmed   Tephrochronology SW flank (Istochniky)
1750 BCE (?) Unknown Confirmed 3 Tephrochronology SW flank (Mokhnataya)
2050 BCE (?) Unknown Confirmed 3 Tephrochronology SW flank (Kruglenky)
4550 BCE (?) Unknown Confirmed   Tephrochronology Plosky and Ostry Tolbachik calderas
5450 BCE (?) Unknown Confirmed   Tephrochronology SW flank and NE flank
5600 BCE (?) Unknown Confirmed   Tephrochronology SW flank
5650 BCE (?) Unknown Confirmed   Tephrochronology SW flank (Bubochka)
6050 BCE (?) Unknown Confirmed   Radiocarbon (uncorrected) SW flank (Lesnaya)
7600 BCE (?) Unknown Confirmed   Radiocarbon (corrected)

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Braitseva O A, Melekestsev I V, Ponomareva V V, Litasova S N, Sulerzhitsky L D, 1981. Tephrochronological and geochronological studies of Tolbachik regional zone of scoria cones. Volc Seism, 1981(3): 14-28 (in Russian).

Braitseva O A, Melekestsev I V, Ponomareva V V, Sulerzhitsky L D, 1995. Ages of calderas, large explosive craters and active volcanoes in the Kuril-Kamchatka region, Russia. Bull Volc, 57: 383-402.

Doubik P, Hill B E, 1999. Magmatic and hydromagmatic conduit development during the 1975 Tolbachik eruption, Kamchatka, with implications for hazards assessment at Yucca Mountain, NV. J Volc Geotherm Res, 91: 43-64.

Erlich E N, 1986. Geology of the calderas of Kamchatka and Kurile Islands with comparison to calderas of Japan and the Aleutians, Alaska. U S Geol Surv Open-File Rpt, 86-291: 1-300.

Fedotov S A, Masurenkov Y P (eds), 1991. Active Volcanoes of Kamchatka. Moscow: Nauka Pub, 2 volumes.

Firstov P P, Ivanov B V, Karpukhina Y V, 1979. Temporal and energetical regularities of volcanic eruptions of Kurile-Kamchatka region in 1956-1976. Akad Nauk SSSR, Sibirsk Otdeleniye Byull Vulk Stantsii, 57: 3-11 (in Russian).

Green J, Short N M, 1971. Volcanic Landforms and Surface Features: a Photographic Atlas and Glossary. New York: Springer-Verlag, 519 p.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Ponomareva V V, Melekestsev I V, Dirksen O V, 2006. Sector collapses and large landslides on late Pleistocene-Holocene volcanoes in Kamchatka, Russia. J Volc Geotherm Res, 158: 117-138.

Vlodavetz V I, Piip B I, 1959. Kamchatka and Continental Areas of Asia. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 8: 1-110.

The massive Tolbachik basaltic volcano is located at the southern end of the dominantly andesitic Kliuchevskaya volcano group. The Tolbachik massif is composed of two overlapping, but morphologically dissimilar volcanoes. The flat-topped Plosky Tolbachik shield volcano with its nested Holocene Hawaiian-type calderas up to 3 km in diameter is located east of the older and higher sharp-topped Ostry Tolbachik stratovolcano. The summit caldera at Plosky Tolbachik was formed in association with major lava effusion about 6500 years ago and simultaneously with a major southward-directed sector collapse of Ostry Tolbachik volcano. Lengthy rift zones extending NE and SSW of the volcano have erupted voluminous basaltic lava flows during the Holocene, with activity during the past two thousand years being confined to the narrow axial zone of the rifts. The 1975-76 eruption originating from the SSW-flank fissure system and the summit was the largest historical basaltic eruption in Kamchatka.