Activity for the week of 27 May-2 June 2009
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
New Activity / Unrest
| Siau Island (Indonesia)
| 2.781°N, 125.407°E
| Elevation 1797 m
CVGHM reported that seismicity from Karangetang increased during 30-31 May and tremor was detected. On 30 May, diffuse white plumes rose 10-50 m high and incandescence was seen at the crater. On 31 May, white emissions from Utama Crater in the N part of the summit region rose 100 m. Incandescent material traveled as far as 2.3 km, mostly down the S flank. Ash plumes that rose 25-700 m were accompanied by thunderous sounds. The Alert Level was raised to 4, the highest level on a scale of 1-4. People were advised not to go within a 3-km-radius of the active area. According to a news article, over 350 people evacuated the area.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), People's Daily Online (China)
| Halmahera (Indonesia)
| 0.32°N, 127.4°E
| Elevation 1357 m
CVGHM reported that during 28 May-2 June seismicity from Makian increased, particularly the occurrence of tremor. Little, if any, increases in emissions were seen. The Alert level was raised to 2 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
| Central Java (Indonesia)
| 7.242°S, 109.208°E
| Elevation 3428 m
Based on ground information from CVGHM, the Darwin VAAC reported that on 27 May an ash plume from Slamet rose to an altitude of 4.3 km (14,000 ft) a.s.l. Analysis of satellite imagery indicated that a possible plume rose to an altitude of 6.1 km (20,000 ft) a.s.l., but ash was not conclusively detected.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Kyushu (Japan)
| 31.593°N, 130.657°E
| Elevation 1117 m
Based on information from JMA, the Tokyo VAAC reported that on 30 May an explosion from Sakura-jima produced a plume that rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted SE. On 31 May, an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l. The next day, eruptions produced plumes that rose to altitudes of 2.1-3.4 km (7,000-11,000 ft) a.s.l. Some plumes drifted S.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
| Bougainville (Papua New Guinea)
| 6.137°S, 155.196°E
| Elevation 1855 m
Based on analysis of satellite imagery, the Darwin VAAC reported that on 2 June an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75 km W.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Komba Island (Indonesia)
| 7.791°S, 123.585°E
| Elevation 633 m
Based on analysis of satellite imagery, the Darwin VAAC reported that during 27 May-2 June ash plumes from Batu Tara rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 25-75 km NW, W, and SW. A thermal anomaly was also identified on satellite imagery on 29 May.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| 42.833°S, 72.646°W
| Elevation 1122 m
Based on web camera views, SERNAGEOMIN reported that during 20-27 May gas-and-ash plumes rose 1.5 km from Chaitén's growing Domo Nuevo 1 and Domo Nuevo 2 lava-dome complex. Collapses originating from unstable slopes generated block-and-ash flows that were sometimes seen from Chaitén town, 10 km SW. Seismicity remained elevated; the hypocenters of the large hybrid earthquakes were located under the W part of the complex at depths of 5-9 km. The Alert Level remained at Red. Based on web camera views, the Buenos Aires VAAC reported that during 28-29 May and 1-2 June ash plumes rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. Thermal anomalies were also seen in satellite imagery on all three days.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Buenos Aires Volcanic Ash Advisory Center (VAAC)
| Halmahera (Indonesia)
| 1.693°N, 127.894°E
| Elevation 1229 m
Based on analysis of satellite imagery, the Darwin VAAC reported that during 27-28 May ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 55-110 km NE.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Sicily (Italy)
| 37.748°N, 14.999°E
| Elevation 3295 m
INGV-CT reported that during 25-31 May the NW-SE-trending fissure E of the Etna summit craters continued (since 13 May 2008) to produce active lava flows to the N of the SE end of the fissure, along the W wall of the Valle del Bove. At least three lava flows were active. Elsewhere on the volcano, activity was restricted to degassing from the Northeast Crater, from the NW and SE Bocca Nuova vents, from the E flank of the Southeast Crater, and along summit fumarolic fields. The activity was observed directly and by utilizing surveillance cameras in Milo (about 11 km ESE).
Source: Sezione di Catania - Osservatorio Etneo (INGV)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 27 May-2 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 ocean entry. The Kupapa'u ocean entry was active until 31 May. On 30 May, a thermal anomaly on the upper TEB flow field was detected on satellite imagery. Pilot reports and satellite imagery analysis on 2 June confirmed active surface lava flows in this area. A small channelized 'a'a lava flow had stagnated above the top of the pali.
The vent in Halema'uma'u crater continued to produce a predominantly white plume, occasionally tinged brown, that drifted mainly SW. Small amounts of ash-sized tephra, including Pele's hair, Pele's tears, and fresh spatter, were retrieved from collection bins placed near the plume during the reporting period. A molten lava pool near the base of the cavity, deep below the floor of the vent, produced incandescence of variable intensity. Sounds resembling rushing gas were sometimes heard in the vicinity of the crater.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| 38.692°S, 71.729°W
| Elevation 3125 m
SERNAGEOMIN reported that scientists aboard an overflight of Llaima on 1 June observed a 2-square-kilometer area with an elevated temperature on the E flank. Several small areas emitted gas and a small cone was forming about 800 m below the crater. They also saw an E-W trending fissure 200 m from the rim of the main crater that was about 300 m long. Brown ash and steam plumes were emitted from different areas of the fissure. The irregularly-shaped summit crater had a few weak fumaroles. The Volcano Alert Level remained at Yellow.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Nevado del Huila
| 2.93°N, 76.03°W
| Elevation 5364 m
INGEOMINAS reported a seismic swarm at Nevado del Huila on 28 May that included M 4 and M 4.8 earthquakes felt by local residents. On 31 May, an episode of tremor was associated with an ash emission seen on a web camera. Another pulse of tremor was detected on 2 June. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").
Source: Servicio Geológico Colombiano (SGC)
| 19.023°N, 98.622°W
| Elevation 5393 m
CENAPRED reported that emissions of steam and gas from Popocatépetl were visible during 27 May-2 June; the plumes contained slight amounts of ash during 27-29 May.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED)
| New Britain (Papua New Guinea)
| 4.271°S, 152.203°E
| Elevation 688 m
RVO reported that during 21-28 May white and occasionally blue plumes from Rabaul caldera's Tavurvur cone rose 1 km above the crater. Incandescence from the summit crater was seen at night.
Source: Rabaul Volcano Observatory (RVO)
| United States
| 60.485°N, 152.742°W
| Elevation 3108 m
AVO reported that during 27 May-2 June seismicity from Redoubt remained low, but above background levels; small discrete earthquakes and rockfall signals in the summit region were recorded. Growth of the lava dome in the summit crater continued. Cloudy conditions obscured satellite and web camera views. AVO warned that the unstable lava dome could fail with little or no warning, leading to significant ash emissions and possible lahars in the Drift River valley. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
KVERT reported that during 22-29 May seismic activity from Shiveluch was above background levels. Steam-and-gas emissions were seen during 21-23 May. Based on video camera views, gas-and-steam plumes containing a small amount of ash rose to an altitude of 4 km (13,100 ft) a.s.l. on 22 May. Analysis of satellite imagery revealed a daily thermal anomaly over the lava dome. The Level of Concern Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
MVO reported that during 22-29 May activity from the Soufrière Hills lava dome was at a low level. On 23 May, a rockfall was detected by the seismic network and contained some low-frequency energy at the onset that may have indicated a small explosion. A small pyroclastic flow on 24 May traveled 1 km E towards the Tar River valley; a resultant ash plume drifted W over Gages Mountain and Plymouth. The Hazard Level remained at 3.
Source: Montserrat Volcano Observatory (MVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
The IG reported that Strombolian activity was seen at night from Tungurahua during 26-28 May, followed by nighttime incandescence at the crater through 1 June. The Washington VAAC reported that during 27-29 and 31 May thermal anomalies were seen on satellite imagery. IG also stated that explosions, "cannon shots," and roaring noises were occasionally reported. On 28 May, steam-and-ash plumes rose to an altitude of 7 km (23,000 ft) a.s.l. and drifted W and SW. Blocks rolled 1 km down the flanks. Ashfall was reported downwind during 28-30 May.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC)
| 16.355°S, 70.903°W
| Elevation 5672 m
Based on SIGMET notices, the Buenos Aires VAAC reported that on 29 and 31 May eruptions from Ubinas produced ash plumes that rose to altitudes of 5.5-6.7 km (18,000-22,000 ft) a.s.l. and drifted NE and SW. Ash was not detected on satellite imagery on 31 May. INGEMMET reported on 1 June a bluish gas plume with some ash content. On 2 June, an explosion was detected and gas-and-ash plumes that rose 0.9-1.5 km drifted E.
Sources: Instituto Geológico Minero y Metalúrgico (INGEMMET), Buenos Aires Volcanic Ash Advisory Center (VAAC)
Criteria & Disclaimers
The Weekly Volcanic Activity Report does not necessarily include all volcanic activity that occurred on Earth during the week. More than a dozen volcanoes globally have displayed more-or-less continuous eruptive activity for decades or longer, and such routine activity is typically not reported here. Moreover, Earth's sea-floor volcanism is seldom reported even though in theory it represents the single most prolific source of erupted material. The Weekly Volcanic Activity Report summarizes volcanic activity that meets one or more of the following criteria:
- A volcano observatory raises or lowers the alert level at the volcano.
- A volcanic ash advisory has been released by a volcanic ash advisory center (VAAC) stating that an ash cloud has been produced from the volcano.
- A verifiable news report of new activity or a change in activity at the volcano has been issued.
- Observers have reported a significant change in volcanic activity. Such activity can include, but is not restricted to, pyroclastic flows, lahars, lava flows, dome collapse, or increased unrest.
Volcanoes are included in the "New Activity/Unrest" section of the Weekly Volcanic Activity Report if the activity occurs after at least 3 months of quiescence. Once a volcano is included in the "New Activity/Unrest" section, updates will remain in that section unless the activity continues for more than 1 month without escalating, after which time updates will be listed in the "Continuing Activity" section. Volcanoes are also included in the "New Activity/Unrest" section if the volcano is undergoing a period of relatively high unrest, or increasing unrest. This is commonly equal to Alert Level Orange on a scale of Green, Yellow, Orange, Red, where Red is the highest alert. Or alert level 3 on a scale of 1-4 or 1-5.
It is important to note that volcanic activity meeting one or more of these criteria may occur during the week, but may not be included in the Weekly Volcanic Activity Report because we did not receive a report.
1. The Weekly Volcanic Activity Report is intended to provide timely information about global volcanism on a weekly basis. Consequently, the report is generated rapidly by summarizing volcanic reports from various sources, with little time for fact checking. The accuracy of the Weekly Volcanic Activity Report is dependent upon the quality of the volcanic activity reports we receive. Reports published in the Bulletin of the Global Volcanism Network are monthly, and more carefully reviewed, although all of the volcanoes discussed in the Weekly Volcanic Activity Report are not necessarily reported in the Bulletin. Because of our emphasis on rapid reporting on the web we have avoided diacritical marks. Reports are updated on the Weekly Volcanic Activity Report web page as they are received, therefore information may be included regarding events that occurred before the current report period.
2. Rapidly developing events lead to coverage that is often fragmentary. Volcanoes, their eruptions, and their plumes and associated atmospheric effects are complex phenomena that may require months to years of data analysis in order to create a comprehensive summary and interpretation of events.
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