Seismogram (CPW), 112 km (70 mi) NW of Mount St. Helens, May 18, 1981

Seismogram from station CPW, 112 km (70 mi) northwest of Mount St. ...

Detailed Description

Annotated seismogram indicates the signals for a Low-Frequency (LF) volcanic earthquake, relative quiescence, and then harmonic tremor as the eruption of May 18, 1980 accelerated. Each horizontal line represents 15 minutes of time.


Image Dimensions: 820 x 703

Date Taken:


CPW seismic station