AVO Semisopochnoi ORANGE/WATCH – Seismicity continues; no unusual activity in satellite images

Aug 7, 2019 21:38 – Seismicity has remained above background with periods of seismic tremor and occasional discrete low-frequency earthquakes. No activity observed in satellite data. It remains possible that activity could increase rapidly and with little warning.

Semisopochnoi is monitored with an on-island seismic network and remotely by satellite and lightning sensors. Furthermore, an infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.