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Monday, September 27, 2004 12:57:33 AM (Pacific Daylight Time, UTC-07:00) ( Mt. St. Helens | Random Stuff )

Clearly visible from the front porch of my house, across the river over there in Washington, Mt. St. Helens is getting restless. Standing in the yard looking at the mountain in the hazy sky, it looked just like it does any other day, but apparently it's been grumbling more than it usually does under the surface - enough for the USGS to take official notice, anyhow.

Here is the seismic-activity recording from Wednesday evening last week (the seismograph readout shows a 12-hour block from noon to midnight UTC, which is 9pm to 5am PDT), which looks pretty normal:

And the following are the subsequent 12-hour periods, from September 23rd on through to this evening...

September 23 0000-1159

September 23 1200-2359

September 24 0000-1159

September 24 1200-2359

September 25 0000-1159

September 25 1200-2359

September 26 0000-1159

September 26 1200-2359

September 27 0000-1159 (partial)

All images come from the webicorders system at the Pacific Northwest Seismograph Network. On the webicorders page, scroll down and see the links under "SEP EHZ UW : St. Helens - Dome Station" for the latest data.

In addition, news reports are now saying that the USGS has issued a "notice of volcanic unrest" for the mountain: "Initially, hundreds of tiny earthquakes that began Thursday morning had slowly declined through Saturday. By Sunday, however, the swarm had changed to include more than 10 larger earthquakes of magnitude 2.0 to 2.8, the most in a 24-hour period since the last dome-building eruption in October 1986, Scott said."

The full Seattle P-I news story can be read here.

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