On 18 November AVO raised the Aviation Color Code for Takawangha to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) based on increased seismicity. The number of small earthquakes detected near the volcano had increased during the previous few days and intensified during 17-18 November. The earthquakes were located at depths of 3-6 km below sea level with the largest magnitudes between 2 and 3. The seismicity possibly indicated magma movement at depth. The intensity of the seismicity was variable during 19-22 November.

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 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.

Source: US Geological Survey Alaska Volcano Observatory (AVO)