Seismic Evidence for Glacier Motion

Abstract

Abstract Unusual seismic signals with weak P phases and well-developed monochromatic shear-wave trains have been recorded and their sources located near College Fiord, Alaska. Epicentral determinations show that they originate on or near glaciers. Some of the events have equivalent earthquake magnitudes of 2.0 to 2.5. These energy sources seem to be compatible with spasmodic glacier movement. Smaller events occur often—as many as 60 per day.