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COLOR CODE: YELLOW
Seismic activity abruptly declined at Pavlof Volcano early Wednesday morning and is presently near background levels, prompting AVO to downgrade the Level of Concern Color Code to YELLOW. Poor weather conditions have prevented direct observation of the volcano, however, the substantial decrease in seismicity implies that eruptive activity--lava fountaining and explosions--has probably abated. The decrease in seismicity may be only a lull in the activity. Typical eruptions at Pavlof are characterized by periods of dimished activity interspersed with the periods of strombolian activity. Renewed lava fountaining and production of local diffuse ash clouds could begin again at any time with little seismic warning. AVO will continue to monitor the volcano closely.
Infrared video taken by the Alaska State Troopers on Monday confirmed that the easternmost of two lava flows was the active flow, and that the eastern summit vent was more active than the western sent. The source of intense steaming low on the north flank that has been intermittently visible to aerial and ground observers for several weeks is not a new flank vent but simply a site where lava is in contact with ice or meltwater. Meltwater channels extend down to the low pass between Pavlof and Paflov Sister and then to the northwest into the Cathedral River drainage.
Pavlof is located 600 miles southwest of Anchorage. The
nearest towns to the volcano are Cold Bay (37 mi SW), King
Cove (30 mi SW), Sand Point (60 mi E), and Nelson Lagoon
(50 mi NE). These towns could expect light ash fall
depending on wind direction and level of eruptive
Seismic activity is monitored in real time at the following volcanoes. Some of the volcanoes listed below may have anomalous seismicity, as noted, but are not considered to be at a dangerous level of unrest.
The seismic swarm that began on 1 August 1996 beneath Iliamna Volcano continued during the past week at an average rate of about 6 earthquakes per day.
Spurr, Redoubt, Augustine, Griggs, Katmai, Trident, Mageik, Martin, Dutton, Akutan, and Makushin volcanoes are all at or near normal levels of seismicity.
AVO maintains a computerized alarm system capable of notifying AVO seismologists during non-business hours should unusual seismic activity occur at monitored Alaskan volcanoes.