David A. Johnston bigraphy, stories - American volcanologist

David A. Johnston : biography

18 December 1949 - 18 May 1980

David Alexander Johnston (December 18, 1949 – May 18, 1980) was an American volcanologist with the United States Geological Survey (USGS) who was killed by the 1980 eruption of Mount St. Helens in Washington. One of the principal scientists on the monitoring team, Johnston died while manning an observation post about 6 miles () from the volcano on the morning of May 18, 1980. He was the first to report the eruption, transmitting the message "Vancouver! Vancouver! This is it!" before being swept away by the lateral blast created by the collapse of the mountain's north flank. Though Johnston's remains have never been found, remnants of his USGS trailer were found by state highway workers in 1993.

Johnston's comprehensive, although truncated, career took him across the United States, where he studied Augustine Volcano in Alaska, the San Juan volcanic field in Colorado, and long-extinct volcanoes in Michigan. Johnston was a meticulous and talented scientist who was known for his analyses of volcanic gases and their relationship to eruptions. This, along with his enthusiasm and positive attitude, made him liked and respected by many of his co-workers. After his death, other scientists lauded his character both verbally and in dedications and letters. Johnston felt that scientists must do what is necessary, including taking risks, to help protect the public from natural disasters. His work and that of his fellow USGS scientists convinced the authorities to close Mount St. Helens to the general public before the 1980 eruption, and to maintain the closure in spite of heavy pressure to re-open the area; their work saved thousands of lives. His story has become part of the popular image of volcanic eruptions and their threat to society, and also part of the history of volcanology. To date, Johnston is one of just two American volcanologists known to have been killed in volcanic eruptions.

Following his death, Johnston was commemorated in several ways, including a memorial fund set up in his name at the University of Washington to fund graduate-level research. Two volcano observatories were established and named after him: one in Vancouver, Washington, and the other on the ridge where he died. Johnston's life and death have been featured in several documentaries, films, docudramas and books about the eruption. Along with other people killed by the volcano, Johnston's name is inscribed on memorials dedicated to their memory.

Eruption

Precursor activity

Since its last eruptive activity in the mid-19th century, Mount St. Helens had been largely dormant. Seismographs were not installed until 1972. This period of more than 100 years of inactivity ended in early 1980. On March 15, a cluster of tiny earthquakes rocked the area around the mountain. For six days, more than 100 earthquakes clustered around Mount St. Helens, an indication that magma was moving. There was initially some doubt as to whether the earthquakes were precursors to an eruption. By March 20, a magnitude 4.2 earthquake shook the wilderness around the volcano. The next day, seismologists installed three seismic recorder stations. By March 24, volcanologists at the USGS—including Johnston—became more confident that the seismic activity was a sign of an impending eruption. After March 25, seismic activity drastically increased. By March 26, more than seven earthquakes over magnitude 4.0 had been recorded, and the next day, hazard warnings were publicly issued. On March 27, a phreatic eruption took place, ejecting a plume of ash nearly into the air.

Similar activity continued at the volcano over the following weeks, excavating the crater, forming an adjacent caldera, and erupting small amounts of steam, ash, and tephra. With each new eruption, the plumes of steam and ash from the volcano rose, eventually climbing to . By late March, the volcano was erupting up to 100 times per day.Bryson, p. 220. Spectators congregated in the vicinity of the mountain, hoping for a chance to see its eruptions. They were joined by reporters on helicopters, as well as mountain climbers.

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Living octopus

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