Activity for the week of 14 May-20 May 2008
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
| 42.833°S, 72.646°W
| Elevation 1122 m
Based on observations of satellite imagery and SIGMET reports, the Buenos Aires VAAC reported that during 14-19 May ash plumes from Chaitén rose to altitudes of 5.5-9.1 km (18,000-30,000 ft) a.s.l. and drifted N, NE, and E. Cloudy conditions often inhibited observations. A thermal anomaly was present in the crater on 19 May.
Based on estimates made during an overflight of the area, ONEMI reported on 14 May that about 90 percent of the town of Chaitén was flooded. SERNAGEOMIN reported that on 15 May ashfall accumulated up to 1 mm thick on a ship and an island to the W, and several areas inland were white due to ash cover. Lahars continued to cause the Chaitén and Blanco-Rayas rivers to overflow, affecting new areas in Chaitén town. The Alert Level remained at Red.
According to news articles, the military evacuated small groups of mostly journalists and troops remaining in areas near Chaitén on 19 May. A court ordered police to use force if necessary to move the few remaining people that refused to evacuate to areas outside of the 50 km high-risk zone.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Buenos Aires Volcanic Ash Advisory Center (VAAC), Reuters
| Sicily (Italy)
| 37.748°N, 14.999°E
| Elevation 3320 m
INGV-CT reported continuous ash emission and periodic Strombolian activity from multiple vents, possibly along an E-trending fissure E of Etna's summit craters, during 10-19 May. Observations were limited due to cloud cover. Ash plumes rose to approximate attitudes of 3.5-7.3 km (11,500-24,000 ft) a.s.l. and sulfur dioxide emissions were elevated. Lava flows that issued from the fissure and another fissure to the N traveled about 6 km E into the Valle del Bove during 13-15 May. Ash-and-gas explosions were occasionally accompanied by roaring noises on 14 May. Explosions and roaring noises were audible on 20 May. [Correction: Ash plumes rose to an altitude of 4 km (13,100 ft) a.s.l.]
Source: Sezione di Catania - Osservatorio Etneo (INGV)
| Central Java (Indonesia)
| 7.54°S, 110.446°E
| Elevation 2910 m
Based on a pilot observation, the Darwin VAAC reported that an ash plume from Merapi rose to an altitude of 11.6 km (38,000 ft) a.s.l. on 19 May. Ash was not identified on satellite imagery.
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 during 15-21 May eruption plumes from Sakura-jima rose to altitudes of 1.8-3.4 km (6,000-11,000 ft) a.s.l. The plumes drifted N, NE, SE, S, and SW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
KVERT reported that seismic activity at Karymsky was above background levels on 11 and 12 May and at background levels the other days during 9-16 May. Gas-and-ash explosions that produced plumes to an altitude of 3.1 km (10,200 ft) a.s.l. may have occurred on 11 and 12 May. Observations of satellite imagery revealed that on 13 May a thermal anomaly was present in the crater and a steam plume drifted 7 km ESE. An ash plume at an altitude of 2 km (6,600 ft) a.s.l. was spotted on 15 May and drifted E. The Level of Concern Color Code remained at Orange.
Based on observations of sateliite imagery, the Tokyo VAAC reported that on 20 May an eruption plume rose to an altitude of 3.4 km (11,000 ft) a.s.l.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
Based on visual observations from HVO and National Park Service (NPS) crews and web camera views, HVO reported that during 14-20 May lava flowed SE through a lava tube system underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex to the Waikupanaha ocean entry. Incandescence was occasionally noted from the TEB vent area. Spatter at the Waikupanaha ocean entry built a second littoral cone.
During the reporting period, Kilauea summit earthquakes were located beneath the Halema'uma'u crater, W of the summit, along the S-flank faults, and along the SW rift zone. The eruption from the vent in Halema'uma'u Crater continued to produce white plumes with minor ash content that drifted mainly NE and occasionally SW. During most nights incandescence was seen at the base of the plume. Seismic tremor was elevated. The sulfur dioxide emission rate was high and fluctuated between 1,320 and 680 tonnes per day when measured on 17 and 18 May, respectively. The background rate was 150-200 tonnes per day.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| 14.382°N, 90.601°W
| Elevation 2569 m
INSIVUMEH reported that during 19-20 May white fumarolic plumes from Pacaya's MacKenney cone drifted W. Lava flows from the base of the NW flank traveled 100 m NW in the area between MacKenney cone and Cerro Chino crater to the N. The seismic network recorded small explosions and occasional tremor.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| Central Chile-Argentina border
| 35.223°S, 70.568°W
| Elevation 3977 m
On 14 May, ONEMI reported that increased fumarolic activity at Planchón-Peteroa was normal and likely caused by atmospheric changes that made the plumes more visible from greater distances. Increased fumarolic activity is common when snow melts in the crater and more steam is produced.
Source: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI)
| New Britain (Papua New Guinea)
| 4.271°S, 152.203°E
| Elevation 688 m
RVO reported that during 13-15 May gas plumes from Rabaul caldera's Tavurvur cone produced a haze to the W and NE. During 15-21 May, ash plumes rose to altitudes of 1.7-2.7 km (5,600-8,900 ft) a.s.l. and drifted NE, N, and NW. Ashfall was reported in areas downwind, including Rabaul Town (3-5 km NW). Occasional roaring noises and incandescence at the base of the plume was noted.
Source: Rabaul Volcano Observatory (RVO)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
KVERT reported that seismic activity at Shiveluch was above background levels on 12 and 14 May and at background levels the other days during 9-16 May; gas-and-ash explosions may have occurred on 14 May. During 9 and 11-15 May, hot avalanches descended the lava dome and fumarolic activity was noted. Observations of satellite imagery revealed that a thermal anomaly was present in the crater daily. During 11-13 May, ash and steam plumes drifted SE, SW, and NW. An ash plume at an altitude of 3.6 km (11,800 ft) a.s.l. was spotted on 14 May. The Level of Concern Color Code remained at Orange.
Based on information from the KEMSD, the Tokyo VAAC reported that on 20 May an eruption plume rose to an altitude of 5.8 km (19,000 ft) a.s.l.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)
| 16.72°N, 62.18°W
| Elevation 915 m
MVO reported that activity at Soufrière Hills increased during 9-19 May. The seismic network recorded 17 rockfalls. An eruptive event on 13 May produced an ash plume to an altitude of 3 km (10,000 ft) a.s.l. and was accompanied by a single long-period earthquake. A blue sulfur dioxide plume was also noted. Ash emissions from two areas in the Gages vent to the W were observed on 15 May, but may have started on 14 May. The resultant ash plume rose about 200 m above the lava dome and drifted W. A small rockfall was noted and gentle roaring noises were reported. A new fumarolic area was seen on the SE side of Chances Peak. Ash emissions from Gages vent continued on 16 May. The Alert Level remained elevated at 4 (on a scale of 0-5).
Based on information from MVO and observations of satellite imagery, the Washington VAAC reported that steam plumes with small amounts of ash continued during 17-19 May and drifted N and WNW.
Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC)
| 1.467°S, 78.442°W
| Elevation 5023 m
The IG reported that although visual observations were occasionally limited due to cloud cover during 14-20 May, ash and steam plumes from Tungurahua were spotted most days and rose to altitudes of 6-8 km (19,700-26,200 ft) a.s.l. Ashfall was reported in areas within 8 km to the SW and W during 14-15 and 17-18 May. On 15 May, Strombolian activity was observed and blocks rolled down the flanks. On 17 and 18 May, "cannon shots" and explosions vibrated large windows in areas to the SW and W. Roaring noises were occasionally heard. On 18 May, a lahar possibly descended a drainage to the W. On 19 May, numerous incandescent blocks rolled about 1.6 km down the flanks following a large explosion. Roaring and "cannon shot" noises were audible and windows vibrated in nearby areas after the large explosion and several others that followed throughout the night. Ashfall was reported in areas W and NW during 19-20 May.
Based on information from IG, the Washington VAAC reported that on 20 May an ash plume rose to an altitude of 7.9 km (26,000 ft) a.s.l. and drifted NW.
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 reports, the Buenos Aires VAAC reported that ash plumes from Ubinas rose to an altitude of 5.5 and 8.5 km (18,000 and 28,000 ft) a.s.l. on 15 and 19 May, respectively. The plumes drifted E and SW.
Source: 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.
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