On September 13, 2011 at 09:29:28 AM a weak tremor of 2.6 magnitude occurred below the crater of Mt Rainier, the famous volcano in Washington near the city of Seattle.
from Earthquake Report:
"This does not mean that the volcano will erupt, but this tremor below the crater can at least be called unusual.
Todays tremor is by far the biggest one since many months.
Typically, up to five earthquakes are recorded monthly near the summit. Swarms of five to ten shallow earthquakes over two or three days take place from time to time, predominantly in the region of 4 km below the summit (near sea level), and are thought to be caused by the circulation of hot fluids beneath Mount Rainier.
Seismic swarms (not initiated with a mainshock) are common features at volcanoes, and are rarely associated with eruptive activity."
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More at: Earthquake Report