David Alexander Johnston was an American United States Geological Survey (USGS) volcanologist who was killed by the 1980 eruption of Mount St. Helens in the U.S. state of Washington. A principal scientist on the USGS monitoring team, Johnston was killed in the eruption while manning an observation post six miles (10 km) away on the morning of May 18, 1980. He was the first to report the eruption, transmitting "Vancouver! Vancouver! This is it!" before he was swept away by a lateral blast; despite a thorough search, Johnston's body was never found, but state highway workers discovered remnants of his USGS trailer in 1993.
The last picture ever taken of Johnston, 13 hours before his death at the eruption site
Johnston using a correlation spectrometer, which measures ultraviolet radiation as an indicator of the sulfur dioxide content of gases ejected from Mount St. Helens. Photographed on April 4, 1980.
Johnston going into the Mount St. Helens crater to sample the lake. Photographed on April 30, 1980.
Johnston sampling the lake
A volcanologist, or volcano scientist, is a geologist who focuses on understanding the formation and eruptive activity of volcanoes. Volcanologists frequently visit volcanoes, sometimes active ones, to observe and monitor volcanic eruptions, collect eruptive products including tephra, rock and lava samples. One major focus of inquiry in recent times is the prediction of eruptions to alleviate the impact on surrounding populations and monitor natural hazards associated with volcanic activity. Geologists who research volcanic materials that make up the solid Earth are referred to as igneous petrologists.
A volcanologist sampling lava using a rock hammer and a bucket of water
