Earthquake swarm at Mount Hood July 8-9, 2019

Release Date:

Earthquakes occurring on tectonic faults and are not directly related to volcanic processes occurring beneath Mount Hood

On the afternoon of July 8, 2019 a swarm of small earthquakes started near Mount Hood, Oregon. As of 11:00 AM PDT on July 9, the Pacific Northwest Seismic Network has located more than 30 earthquakes, all occurring about 1 mile ENE of Government Camp and about 5 miles south of the Mount Hood summit. The earthquakes are relatively shallow (2-3 miles) and are likely too small (maximum magnitude 2.1) to be felt.

Swarms in this area have occurred multiple times over the past two decades, most recently in 2014, with the largest event being a M 2.9 on September 14, 2001. The largest event ever recorded near Mount Hood was a M 4.5 on June 29, 2002, at a location 3 miles south of the summit. Based on similarity to past seismic sequences near Mount Hood and on past studies of seismicity in the Mount Hood area, we infer that these earthquakes are occurring on tectonic faults and are not directly related to volcanic processes occurring beneath Mount Hood.

For more information, see Mount Hood earthquake maps at either Cascades Volcano Observatory or Pacific Northwest Seismic Network.