Activity for the week of 22 February-28 February 2006
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
| Andreanof Islands (USA)
| 52.381°N, 174.166°W
| Elevation 1518 m
AVO reported that the Concern Color Code at Korovin volcano was raised from Green to Yellow on 22 February due to an increase in seismicity at the volcano. Distinct seismic signals indicating unrest were recorded on 4 days between 17 and 22 January, with a sustained 11-minute-long seismic signal on 22 February. After 22 February, seismicity decreased and distinct seismic signals like those recorded earlier were not detected. Clouds obscured satellite views of the volcano after 22 February. A pilot report on the 22nd indicated that the summit area was obscured by clouds, and there were no signs of ashfall on the flanks and no steam plume above the volcano. No obvious signs of activity were seen on 23 February by observers in the village of Atka. AVO received no reports of volcanic activity and there were no indications that an eruption was imminent.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| Papua New Guinea
| 4.08°S, 145.037°E
| Elevation 1807 m
A large eruption began at Manam on 27 February around 1733 from the volcano's Southern Crater. According to the Darwin VAAC, satellite imagery showed an umbrella cloud above the volcano and a strong hot spot. The edges of the ash cloud were ice rich and the eruption height appeared to be about 19 km (~62,300 ft) a.s.l. based on a warm temperature anomaly in the middle of the cloud indicating a stratospheric intrusion.
RVO reported that the strong phase of the eruption declined on 28 February around 0030. During the height of the activity, incandescent lava fragments were thrown 700-800 m high; ejection heights later decreased to 200-300 m. A large amount of ash was deposited on the E part of the island and lava flowed down the SW valley. By 1 March, only gas was emitted from Southern Crater, no noises were heard, and weak incandescence was visible around the vent. Incandescent lava fragments were thrown 100-150 m above the vent and fell into the crater. Main Crater gently emitted occasional ash clouds, and then gas later in the day. Field inspections on 28 February confirmed that a lava flow traveled down the SW valley to about 600 m elevation, a pyroclastic flow traveled down the same valley to about 500 m elevation, and the maximum ash thickness was about 7-8 cm on the E part of the island. After mid-February the seismic station at the volcano was not operating and radio communication with the observer at Bogia ceased. The island is inhabited by about 300 people who returned to the island after evacuating following the 27 January 2005 eruption. The Alert Level at the volcano was at "Stage 2."
Sources: Rabaul Volcano Observatory (RVO), Darwin Volcanic Ash Advisory Centre (VAAC), Agence France-Presse (AFP)
| United States
| 59.363°N, 153.43°W
| Elevation 1252 m
During 21-27 February, seismicity at Augustine was relatively low, but remained above background levels. Seismic data indicated that small rockfalls and avalanches from the lava dome occurred intermittently. A thermal anomaly was visible in the summit area on satellite and camera imagery. These data indicated that the lava dome at the volcano's summit continued to grow slowly. Observations during the report week revealed that a plume composed of variable amounts of gas, steam, and small amounts of ash was emitted intermittently from Augustine's summit. Augustine remained at Concern Color Code Orange.
Sources: US Geological Survey Alaska Volcano Observatory (AVO), Anchorage Volcanic Ash Advisory Center (VAAC)
| 19.514°N, 103.62°W
| Elevation 3850 m
Several small explosions occurred at Colima during 22-26 February. Based on information from the Mexico City MWO, the Washington VAAC reported that an explosion on 22 February produced an ash cloud to an estimated height of 9.1 km (30,000 ft) a.s.l. that drifted NE.
Sources: Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima, Washington Volcanic Ash Advisory Center (VAAC)
| Paramushir Island (Russia)
| 50.686°N, 156.014°E
| Elevation 1103 m
KVERT reported that no significant changes in activity at Ebeko had been seen on satellite imagery or via ground observations for several months, so the Concern Color Code was reduced from Yellow to Green, the lowest level. A weak scent of hydrogen sulfide and chlorine gas was sometimes noted in the town of Severo-Kurilsk, ~7 km from the volcano. Ebeko is not seismically monitored. According to KVERT, it is likely that activity will stay at low levels and an explosive eruption is not imminent in the next weeks.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 1.22°N, 77.37°W
| Elevation 4276 m
During 20-27 February, seismicity continued at Galeras, with an average of 280 small earthquakes occurring per day. On 26 February seismic stations detected a cluster of earthquakes. A shallow M 4.8 volcano-tectonic earthquake was registered below the volcano at 1009, followed by 35 smaller earthquakes. Slight deformation was recorded at the volcano. A flux of about 600 metric tons of sulfur dioxide was measured per day. Steam and gas rose to ~700 m above the volcano (or 16,300 ft a.s.l.). Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").
Source: Servicio Geológico Colombiano (SGC)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
During 17-24 February, Strombolian activity continued at Karymsky. Satellite imagery showed a large thermal anomaly at the volcano's crater and numerous ash plumes extending as far as 117 km. Karymsky remained at Concern Color Code Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 27-28 February, no surface lava flows were visible on Kilauea's Pulama pali fault scarp, which had been the case since 8 February. Lava flowed into the ocean at the East Lae`apuki entry. Background volcanic tremor was at normal levels at Kilauea's summit, with shallow earthquakes continuing to occur beneath the summit area and the upper east rift zone. Volcanic tremor reached moderate levels at Pu`u `O`o. Slight inflation and deflation occurred at the volcano.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| Luzon (Philippines)
| 13.257°N, 123.685°E
| Elevation 2462 m
PHIVOLCS reported that about nine earthquakes related to explosive activity took place at Mayon around 23 February. Cloudy conditions prevented observations of the volcano, but seismic events probably accompanied minor ash explosions. This was supported by reports from residents near the volcano who heard rumbling. The seismic network also recorded two low-frequency volcanic earthquakes associated with shallow magma movement. The sulfur-dioxide flux averaged 1,740 metric tons per day (t/d), similar to values obtained during the last measurement on 28 November 2005. The flux was well above the usual 500 t/d measured at the volcano. Mayon remained at Alert Level 2, with a 6-km-radius Permanent Danger Zone in effect.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
| 19.023°N, 98.622°W
| Elevation 5393 m
During 22-28 February, small steam-and-gas emissions occurred at Popocatépetl. Airphotos taken on 10 February showed a 130-m-diameter lava dome at the bottom of the crater.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)
| El Salvador
| 13.853°N, 89.63°W
| Elevation 2381 m
During 17-24 February, volcanic activity was at moderate levels at Santa Ana. Seismicity was relatively stable, and steam plumes rose to low levels above the volcano. The sulfur-dioxide flux was similar to measurements from previous weeks. The level of water in the lagoon within the crater decreased significantly. The Alert Level at Santa Ana remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.
Source: Servicio Nacional de Estudios Territoriales (SNET)
| 16.72°N, 62.18°W
| Elevation 915 m
Photographs of Soufrière Hills taken during 17-24 February confirmed ongoing lava-dome growth. The newest lobe, which appeared on the dome's NW side on 10 February, continued to grow on all sides. It appeared to have filled in the gap between the lava dome and the N and W crater walls. It also grew significantly to the E, overtopping the older lobe by the end of the report period. After 22 February, incandescent rockfalls were visible at night, coursing down the N,E, and SW sides of the dome and into the Tar River Valley. The sulfur-dioxide flux was low, with an average of 286 metric tons per day.
Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC)
| United States
| 46.2°N, 122.18°W
| Elevation 2549 m
Growth of the new lava dome inside the crater of Mount St. Helens continued during 22-27 February, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. St Helens remained at Volcano Advisory (Alert Level 2); aviation color code Orange.
Source: US Geological Survey Cascades Volcano Observatory (CVO)
| Ryukyu Islands (Japan)
| 29.638°N, 129.714°E
| Elevation 796 m
Based on information from JMA, the Tokyo VAAC reported that during 22-24 February several small eruptions occurred at Suwanose-jima. The highest rising plume reached ~3 km (10,000 ft) a.s.l. after an eruption on 23 February.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
| 1.467°S, 78.442°W
| Elevation 5023 m
Activity at Tungurahua during 26-27 February consisted of emissions of steam and gas, with low ash content. An explosion on the 26th at 1600 produced a NW-drifting gas-and-ash plume to ~3 km above the volcano (or ~26,300 ft a.s.l.). After noon on the 27th, an emission of steam and gas with low ash content rose to ~1 km above the volcano (or 19,750 ft a.s.l.) and drifted NW.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
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.
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