Recent Earthquakes

Recent natural and manmade seismic activity.  Click figure for details.

 Quakes Near Volcanoes

Seismicity in Last 30 Days

Volcano Earthquakes
St. Helens
30 Days Ago Now

Volcanoes without recent seismicity

Adams, Baker, Crater Lake, Glacier Peak, Jefferson, Three Sisters

Some controvery in Earthquake Early Warning

Posted by S. Malone, 08/14/2014

MarketPlace news has a report on the "controversy" between a private version of EEW and the US Geological Survey sponsored version (in which the PNSN is participating).  While there are some mistakes in this report it does summarize some important issues: a cheap, semi-secret, private EEW versus a more expensive, open-information, public EEW.

How frequent is there a Cascadia mega-earthquake?

Posted by S. Malone, 08/10/2014

The Seattle Times has a very good discussion of the different interpretations of deep-sea geologic evidence for the frequency and size of our big earthquakes.  There is no question that they occur, just what some of the evidence for their frequency means.  A more garbled view of the controversy was in the science journal, Nature, last week.

iMUSH active experiment will show on PNSN stations

Posted by S. Malone, 07/20/2014

The iMUSH active experiment will start this Tuesday (Jul 22) night with a number of explosions being set off in boreholes in the general Mount St. Helens area.  The PNSN is making available realtime seismic data from our stations for iMUSH scientists (and anyone) to monitor these shots as they occur. See the iMUSH blog entry for these realtime recordings.

iMUSH experiment is underway

Posted by S. Malone, 06/20/2014

A crew of 15+ scientists in up to 7 vehicles are installing seismic stations in the Mount St. Helens area for a two year experiment.  Checkout the almost daily updates and less frequent blogs for the iMUSH experiment on its WEB PAGE (

Latest Seismo Blog Posts

Is Mount St. Helens seismicity increasing?

July 29, 2014

by Steve Malone

Looking at the "Quakes near volcanoes" plot today shows that 87 earthquakes have been recorded at Mount St. Helens over the past 30 days. This is way above the average for the past many years. Is this significant? Actually, no. Its called a sampling artifact that gives the impression of increased activity. For the details......
Several days of very warm weather has resulted in a couple of large snow avalanches at Mount St Helens but apparently no unusually large ones at other volcanoes. The seismic network at Mount St. Helens is particularly good at picking up the shaking due to large snow avalanches. Two such events on the afternoon of May 14 got our attention. For copies of seismograms and photos......

The PNSN reduces risk within the states of Washington and Oregon by

  • monitoring ground motions within the region in order to better understand earthquake and volcano hazards and their impacts on the physical, economic, political, and social environment,
  • providing the most accurate information about earthquakes and volcanoes as rapidly as possible to public officials, the public, and for education, and
  • advocating comprehensive and cost-effective measures for reducing the harmful effects of earthquakes and volcanoes.