USGS Volcano Hazards Program Volcano Update
AVO update page and observatory web site
A swarm of high-frequency earthquakes began at Little Sitkin volcano on the evening of August 29, 2012 and continued through the night prompting AVO to elevate the Aviation Color Code/Volcano Alert Level to YELLOW/ADVISORY. The rate of anomalous seismicity has varied over the last two days, with the two most active periods being the morning of August 30 and at about 04:00 am AKDT (12:00 UTC) on August 31. The rate of earthquakes began to decline about 06:00 am AKDT (14:00 UTC) on August 31 and currently remains in decline. No eruptive activity occurred. Clouds have obscured satellite images of the area.
AVO is closely monitoring the situation and will issue further updates as conditions change.
Although a 4-station seismic network was installed on Little Sitkin Island in 2005, the volcano has not formally been on AVO's list of seismically monitored volcanoes because of chronic telemetry problems resulting in intermittent and sporadic recording of seismic data. Recent work in June 2012 on the receiving station on Amchitka Island resolved most of the communication issues, and data from the 4 stations on Little Sitkin Island are currently recorded and processed, and AVO continues efforts to establish background seismic levels at the volcano.
Little Sitkin volcano occupies Little Sitkin Island in the western Aleutian Islands, and is within the Aleutian Island National Wildlife Refuge. The active stratovolcano rises 1188 m (3898 ft) in the center-northeastern part of the island. The island is 330 km (200 mi) northwest of the community of Adak, 377 km (234 mi) southeast of Attu, and 2173 km (1350 mi) southwest of Anchorage, Alaska. Little Sitkin has no confirmed historical eruptions, although eruptive activity near the turn of the last century seems probable based on vegetation cover of the youngest-looking lava flows. Three long-lived fumarolic and hot springs areas are known including a cluster of boiling, acidic pools on the west flank of the volcano.
AVO is closely monitoring the situation and will issue further updates as conditions change.
Although a 4-station seismic network was installed on Little Sitkin Island in 2005, the volcano has not formally been on AVO's list of seismically monitored volcanoes because of chronic telemetry problems resulting in intermittent and sporadic recording of seismic data. Recent work in June 2012 on the receiving station on Amchitka Island resolved most of the communication issues, and data from the 4 stations on Little Sitkin Island are currently recorded and processed, and AVO continues efforts to establish background seismic levels at the volcano.
Little Sitkin volcano occupies Little Sitkin Island in the western Aleutian Islands, and is within the Aleutian Island National Wildlife Refuge. The active stratovolcano rises 1188 m (3898 ft) in the center-northeastern part of the island. The island is 330 km (200 mi) northwest of the community of Adak, 377 km (234 mi) southeast of Attu, and 2173 km (1350 mi) southwest of Anchorage, Alaska. Little Sitkin has no confirmed historical eruptions, although eruptive activity near the turn of the last century seems probable based on vegetation cover of the youngest-looking lava flows. Three long-lived fumarolic and hot springs areas are known including a cluster of boiling, acidic pools on the west flank of the volcano.
Update in Common Alerting Protocol (CAP) format
