Takawangha volcano (Tanaga Island, Aleutians): earthquake swarm, alert level raised
Tue, 24 Jan 2017, 19:2619:26 PM | BY: T
The alert level of the volcano was raised to yellow as the Alaska Volcano Observatory detected an energetic earthquake swarm on Tanaga Island 6-7 km ESE of the volcano.
Location of the recent M4 earthquakes beneath Takawangha volcano (yellow circles)
The seismic swarm, which includes two quakes of magnitude 4.1 and 4.4 at 7 and 10 km depth, respectively, started yesterday and is continuing. It might be caused by magma movements at depth resulting in rock-fracturing as intruding magma pressurizes the host rocks to make itself space. It might be a precursor to new activity, although most volcanic earthquake swarms do not end in an eruption (magma often is stalled underground in the process).
No eruptive activity has been detected in satellite data.
There are no known historic eruptions from Takawangha volcano, although it is suspected (from geologic studies) that it's most recent activity was only about 500 years ago. Its neighbor to the west is historically active Tanaga volcano, which last erupted in 1914.