Friday, December 27, 2019

May 18, 1980 the Deadly Eruption of Mount St. Helens

Vancouver! Vancouver! This is it! David Johnstons voice crackled over the radio link from Coldwater Observation Post, north of Mount St. Helens, on the clear Sunday morning of May 18, 1980. Seconds later, the government volcanologist was engulfed in the volcanos gigantic lateral blast. Other people died that day (including three more geologists), but for me Davids death hit very close to home—he was a co-worker of mine at the U.S. Geological Survey offices in the San Francisco Bay area. He had many friends and a bright future, and when Vancouver, the temporary USGS base in Vancouver, Washington, became a permanent institution, it took his name to honor him. Johnstons death, I remember, was a shock to his colleagues. Not just because he had been so alive and so young, but also because the mountain had seemed to be cooperating that spring. Mount St. Helens Background and Eruption Mount St. Helens was long known to be a threatening volcano, having last erupted in 1857. Dwight Crandall and Donal Mullineaux of the USGS, as early as 1975, had pegged it as the most likely of the Cascade Range volcanoes to erupt, and they urged a program of regular monitoring and civic preparations. So when the mountain awoke on March 20, 1980, the scientific community did too. The state of the art technology was pushed—sensors were put in place all around the peak that broadcast their readings to data-logging computers many kilometers away from the foul gases and shuddering ground. Megabytes of clean data (keep in mind, this was 1980) were gathered and accurate maps of the volcano, compiled from laser-ranging measurements, were turned out in mere days. What is routine practice today was brand-new then. The Mount St. Helens crew gave brown-bag seminars to rapt crowds at the USGS offices in the Bay area. It seemed that scientists had a handle on the volcanos pulse and that authorities could be alerted with hours or days of notice, hold orderly evacuations and save lives. But Mount St. Helens erupted in a way that no one planned for, and 56 people plus David Johnston died that fiery Sunday. His body, like those of many others, was never found. The Mount St. Helens Legacy After the eruption, the research continued. The methods first tested at St. Helens were deployed and advanced in later years and later eruptions at El Chichà ³n in 1982, at Mount Spurr and at Kilauea. Sadly, more volcanologists died on Unzen in 1991 and on Galeras in 1993. In 1991, the dedicated research paid off spectacularly at one of the centurys largest eruptions, at  Pinatubo in the Philippines. There, the authorities evacuated the mountain and prevented thousands of deaths. The Johnston Observatory has a good story on the events that led to this triumph, and the program that made it possible. Science served civic authority again at Rabaul in the South Pacific and Ruapehu in New Zealand. David Johnstons death was not in vain. Present-Day St. Helens Today, observation and research at Mount St. Helens is still in full swing; which is necessary, as the volcano is still highly active and has  shown signs of life  in the years since. Among this advanced research is the  iMUSH  (Imaging Magma Under St. Helens) project, which uses geophysical imaging techniques along with geochemical-petrological data to create models of the magma systems underneath the entire area.   Beyond tectonic activity, the volcano has a more recent claim to fame: It is home to the worlds newest glacier, located right in the volcano caldera. This may seem hard to believe, given the setting and the fact that most of the worlds glaciers are in a decline. But, the 1980 eruption left a horseshoe crater, which shields the accumulating snow and ice from the sun, and a layer of loose, insulating rock, which protects the glacier from underlying heat. This allows the glacier to grow with little ablation.    Mount St. Helens on the Web There are lots of web sites that touch on this story; to me, a few stand out.   The USGSs huge  Mount St. Helens site  at the Johnston Cascades Volcano Observatory has a thorough scientific history before, during and after the blast, as well as a survey of the continuing program to watch the subtle breathing of the peak they call MSH in its temporary repose. Poke around the photo gallery, too.The Columbian, the newspaper of the nearby town of Vancouver, Washington,  offers an informative timeline  on the history of Mount St. Helens.  The Atlantic has a  powerful image gallery  of the immediate aftermath.   PS: Eerily enough, there is another David Johnston dealing with volcanoes today in New Zealand. Heres an article of his on how people respond to the threat of eruption. Edited by Brooks Mitchell

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