Activity for the week of 11 January-17 January 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
| United States
| 59.363°N, 153.43°W
| Elevation 1252 m
Explosive activity began at Augustine on 11 January. The day before, AVO increased the Concern Color Code from Yellow to Orange when seismicity began to increase at the volcano. On 11 January at 0444 seismic signals began to be recorded that were interpreted as being associated with explosions at Augustine's summit. The Concern Color Code was increased to Red, the highest level. Another explosion occurred at 0513, and satellite imagery confirmed that an ash plume was produced that rose to ~9.1 km (30,000 ft) a.s.l. and drifted N and E. An ashfall advisory was issued by the National Weather Service. Seismicity decreased after the explosions. During a flight over the volcano, scientists saw volcanic mudflows on the E, S, and W sides of the volcano. Minor rock and snow avalanche deposits were visible high on the SW part of the edifice. According to news articles, several flights were canceled or diverted due to ash in air space.
On 12 January, the Concern Color Code was reduced to Orange. On 13 January, seismicity began to increase. An eruption on the 13th from about 0355 to 0439 produced an ash plume to 10.4 km (34,000 ft) a.s.l. On the 13th, the volcano entered a period of repetitive and explosive eruptions, with explosions occurring at 0444, 0847, 1122, and 1640. Each event produced ash plumes, mudflows, and pyroclastic flows. The ash plumes produced from these eruptions rose higher than 9.1 km (30,000 ft) a.s.l. Ash drifted ESE and a small amount of ash fell in communities of the SW Kenai Peninsula. Explosions on the 13th at 1858 and on the 14th at 0014 were similar in size and duration as the previous four. In response to these eruptions, the National Weather Service issued an ashfall advisory for the western Kenai Peninsula S of Ninilchik. No explosions were recorded later on the 14th. The level of seismic activity declined after an explosion on 14 January at 0016, so the Concern Color Code was reduced to Orange on 15 January at 0945. Observations on 16 January confirmed that pyroclastic deposits were widespread on the volcano's flanks, as seen in web camera images. Also, a small lava dome appeared to have extruded at the summit.
AVO reported on the 16th that the level of seismic activity at the volcano remained above background. It is likely, but not certain, that further explosive activity will occur. Explosive events similar to those of 13 and 14 January could occur with little or no warning.
Sources: US Geological Survey Alaska Volcano Observatory (AVO), Anchorage Volcanic Ash Advisory Center (VAAC), Los Angeles Times
| United States
| 58.172°N, 155.361°W
| Elevation 1863 m
Increased seismicity occurred at Martin during 8 January until at least 15 January. About 300 earthquakes were recorded during 2 days, in contrast to the background rate of ~25 earthquakes per month since the seismic network was installed in 1996. AVO increased the Concern Color Code to Yellow. AVO reported that swarms of earthquakes of this nature are common at volcanoes such as Martin, and do not suggest that eruptive activity is imminent. Satellite data showed nothing unusual, although steaming is frequently observed at the volcano.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| 19.514°N, 103.62°W
| Elevation 3850 m
During 11-15 January, several small explosions at Colima produced ash plumes. The highest rising ash plume was produced by an explosion on 11 December and reached ~9.1 km (30,000 ft) a.s.l. The plume drifted ENE.
Sources: Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima, Washington Volcanic Ash Advisory Center (VAAC)
| Halmahera (Indonesia)
| 1.693°N, 127.894°E
| Elevation 1229 m
Ash from Dukono was visible on satellite imagery on 12 January at a height of ~3 km (10,000 ft) a.s.l., extending SW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| 14.473°N, 90.88°W
| Elevation 3763 m
During 11-16 January, moderate-to-strong explosions at Fuego produced ash plumes that rose to ~1.5 km above the volcano (or 4,900 ft a.s.l.). Incandescent lava was hurled ~40 m high.
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Craig Chesner (Eastern Illinois University, Charleston, Illinois, USA), Sid Halsor, Wilkes Barre University
| 1.22°N, 77.37°W
| Elevation 4276 m
During a flight over Galeras on 13 January, scientists saw a lava dome in the volcano's main crater. Around this time, there was an increase in the amount of seismicity and deformation. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").
Source: Servicio Geológico Colombiano (SGC)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 11-14 January, lava from Kilauea continued to enter the sea at the East Lae`apuki area, building a new lava delta. Surface lava flows were visible on the Pulama pali fault scarp. On 10 January the summit deflation switched abruptly to inflation after a loss of 5.2 microradians. Relatively high tremor occurred at this time. Tremor quickly dropped, becoming weak to moderate when deflation ended, with seismicity punctuated by a few small earthquakes. By 13 January, background volcanic tremor was near normal levels at Kilauea's summit and reached moderate levels at Pu`u `O`o. On 14 January, the lava delta was about 500 m long (parallel to shore) and still only 140 m wide.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| El Salvador
| 13.853°N, 89.63°W
| Elevation 2381 m
During 6-13 January, volcanic activity was moderate at Santa Ana. Seismicity was a bit over normal levels with small earthquakes occurring, which were interpreted as being associated with gas pulses. Continuous low-level emissions of steam and gas originated from the lagoon and from fumaroles within the crater. The sulfur-dioxide flux ranged between 544 and 2,300 metric tons per day. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.
Source: Servicio Nacional de Estudios Territoriales (SNET)
| 14.757°N, 91.552°W
| Elevation 3745 m
During 11-13 January, several explosions occurred at Santa María's Santiaguito lava-dome complex, producing ash plumes that rose to ~1.5 km above the volcano (or 17,300 ft a.s.l.) and drifted SW. Lava avalanches originated from the SW edge of the Caliente dome. An explosion on the morning of 11 January generated a small pyroclastic flow that traveled down Caliente dome to the NE. INSIVUMEH reported on 16 January that a slight decrease in explosive activity was observed at the volcnao during the previous month, with small-to-moderate explosions producing ash clouds that rose to ~1 km above the crater (or 15,650 ft a.s.l.). On the 16th there were reports of a small amount of ashfall in the urban area of San Felipe Retalhuleu.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| 16.72°N, 62.18°W
| Elevation 915 m
Activity at Soufrière Hills remained at elevated levels during 6-13 January. Photographs revealed that the lava dome continued to grow throughout the report period over a broad sector extending from the E around to the N. Numerous small rockfalls continued from the E and NE flanks of the lava dome, adding talus in the upper reaches of the Tar River valley. The sulfur-dioxide flux averaged 724 metric tons per day.
Source: Montserrat Volcano Observatory (MVO)
| 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 11-16 January, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. There were no significant changes in seismicity or deformation during the report period. Small earthquakes continued to be recorded every 2-3 minutes, with slightly larger events occurring intermittently. St Helens remained at Volcano Advisory (Alert Level 2); aviation color code Orange.
Source: US Geological Survey Cascades Volcano Observatory (CVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
Small-to-moderate explosions at Tungurahua were preceded by long-period earthquakes during 11-16 January. An explosion on 11 January produced a plume with a moderate amount of ash. The plume drifted E.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington 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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