Mount Hood, Oregon
Seismic Activity, June 2002

Submitted at 16:35 PDT, June 29, 2002

Volcanoes in the Cascade Range are all at normal levels of background seismicity. These include Mount Baker, Glacier Peak, Mount Rainier, Mount Adams, and Mount St. Helens 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.

Mount Hood earthquake swarm: The strongest earthquake in the Mount Hood area in decades occurred at 07:36 PDT today. The magnitude 4.5 event, which was located about 4.5 km south of the summit at a depth of 6 km, was widely felt. Hundreds of aftershocks followed, including two >M3. Typically, several earthquake swarms occur each year at Mount Hood.

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.