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Earthquake Swarm Occurring at Mount Hood

October 10, 2017

Swarms common in the vicinity of Mount Hood.

An earthquake swarm began near Mount Hood Monday night ~7 km (4.3 miles) south-southeast of the summit in the White River Valley, an area that commonly exhibits seismicity. It started October 9 at 19:51 UTC (12:51 PDT local) with the largest earthquake a M2.8 at 2:45 UTC on October 10 (1945 PDT on October 9). 14 earthquakes have been located by the Pacific Northwest Seismic Network (PNSN) through October 11, all with depths of 7-8km (4.3 - 5 miles) below sea level.

Such swarms are common in the vicinity of Mount Hood, with the last swarm occurring in May 2016 (largest event M 2.9). Summaries of past swarms near Mount Hood can be found on the PNSN website and on the Mount Hood monitoring webpage.