Earthquake swarm under Takawangha volcano, Aviation Color Code raised to Yellow, Alaska

Seismic activity under Takawangha volcano, Alaska increased over the past couple of days and intensified on November 18, 2022, forcing the Alaska Volcano Observatory (AVO) to raise the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory.

• The last known eruption at this volcano took place in 1550 CE (VEI unknown)

The earthquakes, the largest with magnitudes between 2 and 3, have preliminary depths of about 3 to 6 km (2 to 4 miles) below sea level.¹

AVO said this activity may be due to the movement of magma beneath the volcano.

No eruptive activity has been detected in satellite or other monitoring data.

Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.  

Geological summary

Takawangha is a youthful volcano with an ice-filled caldera on northern Tanaga Island, near the western end of the Andreanof Islands.

It lies across a saddle from the historically active Tanaga volcano to the west; older, deeply eroded volcanoes lie adjacent to the east.

The summit of the dominantly basaltic to basaltic-andesite volcano is largely ice covered, with the exception of five Holocene craters that during the last few thousand years produced explosive eruptions and lava flows that reached the lower flanks.

No historical eruptions are known, although radiocarbon dating indicates explosive eruptions have occurred within the past several hundred years.

This volcano is located within the Aleutian Islands, a UNESCO Biosphere Reserve property.²

References:

¹ AVO/USGS Volcanic Activity Notice – Takawangha – November 19, 2022

² Takawangha – Geological summary – GVP