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Earthquake swarm at Mount Hood

March 9, 2012

Starting at approximately 22:00 pm PST on March 7, 2012, a small swarm of earthquakes has been occurring near Mount Hood.

The earthquakes locate approximately 4 miles south-southwest of the summit of the volcano (~1 mile east of Government Camp) at depths of 2-4 miles. Between 22:00 PST March 7 and 16:00 PST March 9, over a dozen small earthquakes have been located by the Pacific Northwest Seismic Network (PNSN), with magnitudes ranging from 0.0 to 1.7. Typically, several earthquake swarms occur each year at Mount Hood, with some lasting for hours, others lasting for days to weeks. The March 7-9 swarm locates in roughly the same area as previous swarms, including swarms that occurred in February 1998 and September 2001. It is located 2-3 miles west of a swarm that occurred 22-23 February 2012.

For more details about Hood seismicity, visit the PNSN Mount Hood web page. For background information about swarms at Mount Hood, visit the PNSN web site for an excellent blog posting at PNSN Hood swarm blog.