Volcano watchers said Saturday the Mount Rainier earthquake swarm rates continued to decrease.
The Cascades Volcano Observatory and Pacific Northwest Seismic Network recorded 464 events since the start of the current swarm Tuesday and said the largest so far was a magnitude 2.4 that occurred at 12:23 p.m. Friday.
“Seismicity has decreased” from 30 events per hour at the peak to a few per hour as of Saturday morning, the U.S. Geological Survey said Saturday.
“The earthquakes are mainly spread between 1.5-4 miles (2-6 km) beneath the summit. There have been no changes in ground deformation or other monitoring data,” the agency said.
The USGS also reiterated there was no indication that the swarm – the largest at Mount Rainier since recording began in 1982 — is associated with changes to the magma and do not indicate an impending eruption. Rather the activity likely is due to the circulation of hydrothermal fluids along preexisting faults beneath the volcano.
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