By SHANNON HAUGLAND
Sentinel Staff Writer
The Alaska Volcano Observatory said today that the “swarm” of earthquakes under the Mt. Edgecumbe volcano is continuing, but officials repeated their previous statement that it’s no cause for concern by the public.
“May volcanoes experience earthquake swarms that taper off without an eruption,” said the U.S. Geologic Survey in today’s 1 p.m. update. “If renewed volcanic activity were to occur, we would expect that many more earthquakes would be observed. AVO has no plans to supplement the regional seismic network at this point but has this capability should conditions warrant.”
Earlier this week the observatory reported that the earthquake swarm started around 2 a.m. Monday. Since then scientists have been keeping the public informed through the media.
On the first day of the swarm the highest magnitude detected was 2.8 on the Richter scale. Earthquake activity has been slowly declining since early Tuesday, “although as many as several small earthquakes continue to be detected every hour,” the USGS observatory said.
The magnitudes of individual earthquakes in this continuing activity have ranged from about M1.7 down to M0.5 or smaller.
Today’s report said that the observatory does not have local seismic instruments in the area, and the closest station is in Sitka, about 15 miles (25 km) to the east of the volcano.
“Because the volcano is not instrumented, it currently has an Aviation Color Code and Volcano Alert Level (for ground hazards) of UNASSIGNED/UNASSIGNED,” the report said. “AVO has brought additional distant seismic stations from the regional network into its analysis system to better monitor the seismic swarm and is conducting additional retrospective analyses of seismic data.”
The observatory said satellite images from high resolution sensors and web camera images (from the FAA) show no superficial changes related to volcanic unrest. Analysis of Synthetic Aperture Radar (SAR) data is underway to evaluate if topographic changes have occurred over the past several years.
The update also had information about other volcanoes in Alaska, including the Great Sitkin Volcano, Davidof Volcano and Semisopochnoi Volcano in the Aleutians, the Pavlof volcano in the Alaska Peninsula. Three are erupting, and the Davidof volcano is showing patterns similar to Mt. Edgecumbe’s, although the “swarms” were first detected in January.
David Schneider, research geophysicist, said the volcano observatory will continue to watch Sitka, as long as the swarms continue, and update the public if there are significant changes.
“This activity has got our attention and we’ll continue to do retrospective studies as well as looking at new data for the foreseeable future,” he said.
At the volcano observatory David Schneider said scientists will continue to watch Sitka as long as the swarms continue, and update the public if there are significant changes.
“This activity has got our attention and we’ll continue to do retrospective studies as well as looking at new data for the foreseeable future,” he said.
The most recent eruption of Mt. Edgecumbe preserved in the geologic record was about 4,500 years ago, scientists say.
