Description of the Volcanic Event: More Details

Before May 18

A. Elevation 1. Before 1980 the elevation—9,677 feet 2. The peak stood 5,000 feet above its base before the eruption B. Previous eruption 1. Steam and ash eruptions from 1831 to 1857 2. Dormant for 123 years C. Sequence of events in 1980 1. Earthquake on March 20, 1980 2. Series of thousands of shallow earthquakes directly below the mountain in the following week 3. First eruption of steam and ash on March 27, 1980 4. North slope of the volcano began to bulge at rate of 3 ft. per day 5. Harmonic tremors began on April 1, 1980 as magma moved upward; earthquakes intensified

Reference
Austin, Lumsden, Morris, and Vardiman. Mt. St. Helens Tour Guidebook. Institute for Creation Research, 1997.