Magma stores are recharging inside Mount St. Helens, setting off a swarm of small earthquakes since last month, according to the U.S. Geological Survey.
Since the catastrophic eruption of May 18, 1980, scientists have been conducting research and collecting data on the volcano to learn more about its typical behavior.
Since March 14, a number of small earthquakes have occurred beneath the volcano at a depth between 1.2 to 4 miles. The earthquakes have low magnitudes of 0.5 or less, with the largest a 1.3.
Over the last eight weeks, there have been more than 130 earthquakes located by the Pacific Northwest Seismic Network and many more that are too small to be detected.
The USGS says the earthquake rates have been steadily increasing since March, reaching nearly 40 located earthquakes per week, but there are no signs of an imminent eruption.
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