Cascade Range Current Update
University of Washington, Pacific Northwest Seismograph Network, Seattle, Washington
Volcanoes in the Cascade Range are all at normal levels of background seismicity except for Mount St. Helens. See Mount St. Helens update below.
Other volcanoes include Mount Baker, Glacier Peak, Mount Rainier, and Mount Adams in Washington State; Mount Hood, Mount Jefferson, Three Sisters, Newberry, and Crater Lake, in Oregon; and Medicine Lake, Mount Shasta, and Lassen Peak in northern California.
USGS Cascades Volcano Observatory, the Pacific Northwest Seismograph Network at the University of Washington, and the USGS Northern California Seismic Network and Volcano Hazards Team in Menlo Park, California, monitor the major volcanoes in the Cascade Range of northern California, Oregon, and Washington.
Mount St. Helens Update
Increased seismicity overnight prompted raising the alert level to Volcano Advisory (Alert Level 2) at 10:40 A.M., PDT, this morning. Throughout the day the seismic energy level has remained at an elevated with a rate of 3-4 events per minute including an increase in the number of events between Magnitude 2 and 3. All earthquake locations are still shallow and in or below the lava dome. In addition, initial data from the GPS instrument on the lava dome that was repaired Monday morning suggest that the site moved a few inches northward Monday and Tuesday, but has since been stable. Such movement is not surprising in light of the high seismicity levels. A USGS field crew continued their deployment of GPS equipment today in order to monitor any ground movement on the lava dome, crater floor, or lower slopes of the volcano. Another gas flight this morning produced a result of no significant volcanic gas detected, as was the case on Monday. Two press conferences were held at CVO to update the media. Tomorrow’s field work includes continued GPS deployments.
The current hazard outlook is unchanged from that outlined in this morning’s Volcano Advisory. Updated wind forecasts from the National Oceanic and Atmospheric Administration coupled with an eruption model indicate that the wind direction will shift from northwesterly to northeasterly tonight. Therefore any ash clouds produced tonight will drift southwestward.
Confusion at this morning’s press briefing at CVO regarding Alert Levels resulted in numerous calls to emergency management agencies from the public about which is the correct level. We are at Alert Level Two—Volcano Advisory. Explanation of the alert-level scheme can be found on the “News and Current Events” web site below.
For past updates and notices see past updates at:
A few photographs of recent fieldwork and of the volcano can be obtained from:
Daily updates of earthquake data and other information can be found on the WORLD WIDE WEB at URL:
Our "News and Current Events" webpage now contains "Quick Links" to the current update, current photos, and the University of Washington Mount St. Helens seismic page, plus other useful "Background" webpages on Mount St. Helens, including an explanation of the Cascade Range alert-level scheme.
[Cascade Range Current Activity Menu] ...
[Cascade Range Volcanoes and Volcanics Menu] ...
[Mount St. Helens Current Activity Menu] ...
[USGS Volcano Hazards Program Updates Page (includes Alaska, Hawaii, and Long Valley)] ...
[University of Washington's Pacific Northwest Earthquake Information (current seismicity)]