AVO Semisopochnoi ORANGE/WATCH – Seismicity remains elevated.

Sep 10, 2019 20:12 – Low-level eruptive activity may be continuing at Semisopochnoi. Seismic activity over the past day remains elevated with low-frequency earthquakes but there were no explosions detected in regional infrasound data. Satellite observations were mostly obscured by clouds over the past day.

Semisopochnoi is monitored with an on-island seismic network and remotely by satellite and lightning sensors. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.