Mount St. Helens, Washington
Summary of Mount St. Helens Seismic Activity,
July 1996


The following information is provided by the U.S. Geological Survey's Cascades Volcano Observatory and by the University of Washington's Geophysics Program.

Earthquake activity beneath Mount St. Helens remained at a low level during July 1996. Twelve earthquakes were recorded beneath the volcano during the month. None of these earthquakes exceeded magnitude 2.0. The number of earthquakes per month since January 1996 has fluctuated between 10 and 19. Activity at the volcano remains at a safe, background level.

Caption: Cross-sectional view showing the locations of earthquakes beneath Mount St. Helens during July 1996. The cross-section represents a vertical slice of the crust downward from line A-A' in the map view. The earthquakes occurred in and around the magma conduit system that leads from the magma reservoir to the dome. In this graph, 0 depth is referenced to 1.5 km (about 1 mile) below the current summit of Mount St. Helens (8,363 feet above sea level). Data and graph provided by the Geophysics Program, University of Washington.

Caption: Graph showing relationship between time and depth of earthquakes beneath Mount St. Helens from August 1, 1995 to July 31, 1996. In this graph, 0 depth is referenced to 1.5 km (about 1 mile) below the current summit of Mount St. Helens (8,363 feet above sea level). Data and graph provided by the Geophysics Program, University of Washington.