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Maximum magnitude of Sunday quakes was 2.7 near Government Camp, according to USGS

COURTESY PHOTO: U.S. GEOLOGICAL SURVEY/WESTON THELEN - The black circles show the locations of earthquakes at Mount Hood dating back to 2010 and the red circles depict the current swarm. Both are sized by magnitude. Blue triangles are current seismic stations. Dark lines are highways around the volcano.If you were near Government Camp on Mount Hood on Sunday, you might have felt some rumbling. Starting just after noon Jan. 17, was what the U.S. Geological Survey is calling an "earthquake swarm."

The first tremor occurred at 2:55 p.m., as recorded by the Pacific Northwest Seismic Network and was a magnitude 1.7 earthquake. Since then, there have been more than 100 tremors reported. The two most notable registered magnitudes of 2.9 and 2.7. USGS officials said the 2.9-magnitude quake occurred at 3:26 p.m. and the 2.7-magnitude quake was at 3:38 p.m. One was just over 3 miles northeast of Government Camp. The other was 2.5 miles northeast of Government Camp. The last known quake was recorded by the PNSN at 10:09 p.m. Jan. 17.

"Since noon local time on Jan. 17, there have been over 100 individual earthquakes in an area south of the summit of Mount Hood," the USGS reported around 8 p.m. on Sunday. "At the time of this statement, the PNSN has located several 10's of these earthquakes with a maximum magnitude of M2.7 and depths mostly around 5 kilometers (3 miles) below sea level."

COURTESY PHOTO: U.S. GEOLOGICAL SURVEY/WESTON THELEN - The top graph depicts the event rate per week of earthquakes around Mount Hood since 2010. Each spike represents a swarm of earthquakes at the volcano. The current swarm is at the right margin of the plot. The bottom figure shows th depth of earthquakes plotted in time since 2010. The time axis is the same as the top plot.USGS officials also assured the public that "swarms at Mount Hood are common and account for most of the seismicity at the volcano; they can last hours to days" and that "the earthquakes are associated with regional faulting and are not a sign of changes in volcanic activity."

The location of the earthquakes is said to be similar to that of other swarms that occurred on the mountain in 2009, 2012, 2014 and 2020.

The USGS is inviting people who felt the earthquakes on Jan. 17 to contribute information on the agency's website.

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