Helens in Washington State on May 18, 1980, is certain to be remembered as one of the most significant geologic events in the United States of the 20th century.The explosion, on May 18, was initiated by an earthquake and rockslide involving one-half cubic mile of rock.
In Spirit lake, north of the volcano, an enormous water wave, initiated by one-eighth cubic mile of rockslide debris, stripped trees from slopes as high as 850 feet above the pre-eruption water level.
The total energy output, on May 18, was equivalent to 400 million tons of TNT - approximately 20,000 Hiroshima-size atomic bombs.
On May 18 and also during later eruptions, critical energy thresholds were exceeded by potent geologic processes which were able to accomplish significant changes in short order.
These processes challenge the traditional uniformitarian way of thinking about how the earth works, and serve as a miniature laboratory for catastrophism.
Institute for Creation Research scientists have spent three summers investigating the geologic changes which have occurred at the volcano.
Four of the most significant discoveries are summarized in this short report.RAPIDLY FORMED STRATIFICATION Up to 400 feet thickness of strata have formed since 1980 at Mount St. These deposits accumulated from primary air blast, landslide, waves on the lake, pyroclastic flows, mudflows, air fall, and stream water.Perhaps the most surprising accumulations are the pyroclastic flow deposits amassed from ground-hugging, fluidized, turbulent slurries of fine volcanic debris, which moved at high velocities off the flank of the volcano as the eruption plume of debris over the volcano collapsed.These deposits include fine pumice ash laminae and beds from one millimeter thick to greater than one meter thick, each representing just a few seconds to several minutes of accumulation.A deposit accumulated in less than one day, on June 12, 1980, is 25 feet thick and contains many thin laminae and beds.Conventionally, sedimentary laminae and beds are assumed to represent longer seasonal variations, or annual changes, as the layers accumulated very slowly. Helens teaches us that the stratified layers commonly characterizing geological formations can form very rapidly by flow processes.