Small seismic swarm at Mount Hood, August 18, 2012.

Release Date:

Such small swarms are not uncommon at Hood, with the most recent occurring December 11, 2011, and are considered by CVO and the PNSN to be part of the background “normal” level of activity at Hood.

According to the Pacific Northwest Seismic Network (PNSN), a short-lived swarm of small earthquakes (maximum Magnitude 1.8) occurred 1-2 km south of Mount Hood on August 18, 2012. The swarm featured 15 locatable events occurring between 1000-2130 PDT, with depths ranging from 3-6 km below the summit.