SI / USGS Weekly Volcanic Activity Report

Cleveland (United States) - Report for 24 June-30 June 2009 - NEW

Wed, 01 Jul 2009 02:45:45 -0500

A small explosive eruption of Cleveland on 25 June prompted AVO to raise the Volcano Alert Level to Watch and the Aviation Color Code to Orange. An ash cloud that detached from the volcano was seen on satellite imagery moving S at an estimated altitude of 4.6 km (15,000 ft) a.s.l. No further activity was reported. On 27 June, AVO lowered the Volcano Alert Level to Advisory and the Aviation Color Code to Yellow.

Source: Alaska Volcano Observatory (AVO)

Sarychev Peak (Russia) - Report for 24 June-30 June 2009 - NEW

Wed, 01 Jul 2009 02:45:45 -0500

SVERT reported that an intense thermal anomaly from Sarychev Peak was detected on satellite imagery during 24-30 June. Gas-and-steam plumes drifted 9 km NW on 24 June, S on 26 June, 26 km SSE on 28 June, and 40 km SE at an altitude of 3 km on 29 June.

Source: Sakhalin Volcanic Eruption Response Team (SVERT)

Arenal (Costa Rica) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

OVSICORI-UNA reported that during May activity originating from Arenal's Crater C consisted of gas emissions, sporadic Strombolian eruptions, and occasional avalanches that traveled down the SW, S, and N flanks. Acid rain and small amounts of ejected pyroclastic material affected the NE and SE flanks. Small avalanches traveled down several ravines. Crater D produced only fumarolic activity. A small eruption on 16 June was verified by field observations on 17 June. The eruption caused avalanches that descended the S flank to an 800-m elevation a.s.l. An ash plume drifted W.

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Bagana (Papua New Guinea) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

Based on analysis of satellite imagery, the Darwin VAAC reported that on 27 June an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 110 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Batu Tara (Indonesia) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

Based on analysis of satellite imagery, the Darwin VAAC reported that during 25-30 June ash plumes from Batu Tara rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted 35-130 km SW, W, and NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Chait�n (Chile) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

Based on web camera views from the S, SERNAGEOMIN reported that during 16-23 June gas-and-ash plumes rose 1.5 km from Chait�n's growing Domo Nuevo 1 and Domo Nuevo 2 lava-dome complex. Collapses originating from unstable slopes generated block-and-ash flows. The Alert Level remained at Red. Based on SIGMET notices and web camera views, the Buenos Aires VAAC reported that during 24-25 and 27-28 June ash plumes rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. and drifted W, S, E, and NE.

Sources: Servicio Nacional de Geolog�a y Miner�a (SERNAGEOMIN), Buenos Aires Volcanic Ash Advisory Center (VAAC)

Dukono (Indonesia) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

Based on analysis of satellite imagery, the Darwin VAAC reported that on 28 June an ash plume from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75 km N.

Source: Darwin Volcanic Ash Advisory Center (VAAC)

Galeras (Colombia) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

INGEOMINAS reported that during 22-23 June gas plumes rising from Galeras contained some ash. An overflight on 23 June revealed that temperatures in the main crater measured between 60 and 120 degrees Celsius, except for a small zone where the temperature measured 220 degrees Celsius. Gas emissions originated from the periphery of the main crater. On 26 June, seismicity similar to that seen prior to previous eruptions, along with low rates of gas emissions, prompted INGEOMINAS to raise the Alert Level to II (Orange; "probable eruption in term of days or weeks").

Source: Instituto Colombiano de Geolog�a y Miner�a (INGEOMINAS)

Kilauea (United States) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

During 24-30 June, HVO reported that lava flowed SE from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the Waikupanaha and Kupapa'u ocean entries. Thermal anomalies detected in satellite images and visual observations revealed active surface flows on the pali and on the TEB flow field. Explosions from both ocean entries were occasionally reported. On 28 June, officials reported a wide swath of lava flows descending the pali. The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW. Small amounts of ash-sized tephra, including Pele's hair and fresh spatter, were retrieved from collection bins placed near the plume during the reporting period. A molten lava pool (54 m in diameter) near the base of the cavity, about 290 m below the floor of the crater, produced incandescence of variable brightness. The level of the lava pond rose periodically. Sounds resembling rushing gas and rockfalls were occasionally heard in the vicinity of the crater. The sulfur dioxide emission rate at the summit remained elevated; measurements were 800 tonnes per day on 24 and 26 June. The 2003-2007 average rate was 140 tonnes per day.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Rabaul (Papua New Guinea) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

RVO reported that during 19-25 June gray ash plumes from Rabaul caldera's Tavurvur cone rose 1.5 km above the crater and produced ashfall in Rabaul town (3-5 km NW) and surrounding areas. Incandescence from the summit crater was seen at night. Based on analysis of satellite imagery, the Darwin VAAC reported that during 26-28 June ash plumes rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted 35-75 km NW and W.

Sources: Rabaul Volcano Observatory (RVO), Darwin Volcanic Ash Advisory Centre (VAAC)

Redoubt (United States) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

AVO reported that during 24-29 June seismicity from Redoubt was low, but remained above background levels. Web camera images showed continued steaming from the lava dome at the summit. No ash signals were observed in radar or satellite imagery. Occasional observations, the low level of seismicity, and low gas emissions suggested that the growth of the lava dome had significantly slowed. On 30 June, AVO lowered the Volcanic Alert Level to Advisory and the Aviation Color Code to Yellow.

Source: Alaska Volcano Observatory (AVO)

Sakura-jima (Japan) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

Based on information from JMA, the Tokyo VAAC reported that during 24-30 June explosions from Sakura-jima sometimes produced plumes that rose to altitudes of 2.1-3.4 km (7,000-11,000 ft) a.s.l. The plumes drifted NE, E, and S.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Sangay (Ecuador) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

Based on a pilot observation, the Washington VAAC reported that on 26 June an ash plume from Sangay rose to an altitude of 7.6 km (25,000 ft) a.s.l. The suspected ash was seen on satellite imagery drifting less than 30 km W.

Source: Washington Volcanic Ash Advisory Center (VAAC)

Santa Mar�a (Guatemala) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

INSIVUMEH reported that on 26 and 29 June explosions from Santa Mar�a's Santiaguito lava dome complex produced ash plumes that rose to altitudes of 2.9-3.3 km (9,500-10,800 ft) a.s.l. and drifted W and SW. Fumarolic plumes rose 100-200 m above Caliente dome. On 26 June, the seismic network detected a lahar that travelled S down the Nima I river. Steam plumes and a sulfur odor rose from the deposits. The lahar was 15 m wide and 1 m thick at the toe, and carried blocks up to 1.5 m in diameter.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Shiveluch (Russia) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

KVERT reported that during 19-26 June seismic activity from Shiveluch was above background levels. Based on interpretations of seismic data, steam-and-gas plumes with some ash content were emitted during the reporting period; ash plumes possibly rose to an altitude of 6.8 km (20,000 ft) a.s.l. On 20 June, ash plumes seen on a video camera rose to an altitude of 5 km (16,400 ft) a.s.l. Gas-and-steam activity was observed at other times during the reporting period. Analysis of satellite imagery revealed a daily thermal anomaly over the lava dome. Ash plumes were also seen on satellite imagery drifting 114 km S during 20 and 22-24 June and more than 100 km SW and NE on 25 June. A pyroclastic flow occurred on 25 June. The Level of Concern Color Code remained at Orange. Based on analysis of satellite imagery and information from KEMSD, the Tokyo VAAC reported that during 27-28 and 30 June eruptions produced plumes that rose to altitudes of 4.9-7 km (16,000-23,000 ft) a.s.l.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)

Slamet (Indonesia) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

CVGHM reported that during 8-28 June tephra was ejected 50-700 m above Slamet's crater and incandescent material was ejected 50-300 m above the crater. Booming noises were reported. During 23-29 June, incandescence and ash emissions were not observed. On 29 June, CVGHM lowered the Alert Level for Slamet to 2 (on a scale of 1-4) because of decreased seismicity and emissions.

Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

Soufri�re Hills (United Kingdom) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

MVO reported that during 19-26 June activity from the Soufri�re Hills lava dome was at a low level. On 20 June, a small pyroclastic flow that traveled E down the Tar River valley produced a small ash cloud that drifted W. The Hazard Level remained at 3.

Source: Montserrat Volcano Observatory (MVO)

Tungurahua (Ecuador) - Report for 24 June-30 June 2009

Wed, 01 Jul 2009 02:45:45 -0500

The IG reported that tremor and explosions from Tungurahua were detected by the seismic network almost daily during 23-30 June. A plume with low ash content rose to an altitude of 7 km (23,000 ft) a.s.l. on 23 June and drifted W, and a small ash plume rose 200 m above the crater on 29 June. Cloud cover frequently prevented observations during the rest of the reporting period. Ashfall was occasionally reported in areas to the W and SW. Sounds resembling blocks rolling down the flanks and "cannon shot" noises were sometimes reported. On 23 June, lava fountains at the summit were observed and blocks ejected from the crater rolled as far as 1 km down the flanks. On 27 June, the seismic network possibly detected lahars in area drainages.

Source: Instituto Geof�sico-Escuela Polit�cnica Nacional (IG)