David A. Johnston
Encyclopedia
David Alexander Johnston (December 18, 1949 – May 18, 1980) was an American volcanologist
Volcanologist
A volcanologist is a person who studies the formation of volcanoes, and their current and historic eruptions. Volcanologists frequently visit volcanoes, especially active ones, to observe volcanic eruptions, collect eruptive products including tephra , rock and lava samples...

 with the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS) who was killed by the 1980 eruption
1980 eruption of Mount St. Helens
The 1980 eruption of Mount St. Helens, a stratovolcano located in Washington state, in the United States, was a major volcanic eruption. The eruption was the only significant one to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in California...

 of Mount St. Helens
Mount St. Helens
Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is south of Seattle, Washington and northeast of Portland, Oregon. Mount St. Helens takes its English name from the British diplomat Lord St Helens, a...

 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
Lateral eruption
A lateral eruption, also called a flank eruption or lateral blast if explosive, is a volcanic eruption that takes place on the flanks of a volcano instead of at the summit. Lateral eruptions are typical at rift zones where a volcano is breaking apart...

 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
Augustine Volcano
Augustine Volcano is a Lava Dome Complex on Augustine Island in southwestern Cook Inlet in the Kenai Peninsula Borough of southcentral coastal Alaska, southwest of Anchorage. The Alaska Volcano Observatory currently rates Mount Augustine as Level of Concern Color Code Green for aviation and the...

 in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

, the San Juan volcanic field
San Juan volcanic field
The San Juan volcanic field, located in southwestern Colorado, contains two distinct phases of volcanism. The earlier volcanism is Oligocene in age, and consists of largely intermediate composition lavas and breccias. A few ash flow tuffs also constitute this phase of volcanism. Later volcanism is...

 in Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

, and long-extinct volcanoes in Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

. Johnston was a meticulous and talented scientist who was known for his analyses of volcanic gas
Volcanic gas
|250px|thumb|right|Image of the [[rhyolitic]] [[lava dome]] of [[Chaitén Volcano]] during its 2008-2010 eruption.Volcanic gases include a variety of substances given off by active volcanoes...

es 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 prior to 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
University of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...

 to fund graduate-level research. Two volcano observatories were established and named after him: one in Vancouver
Vancouver, Washington
Vancouver is a city on the north bank of the Columbia River in the U.S. state of Washington. Incorporated in 1857, it is the fourth largest city in the state with a 2010 census population of 161,791 as of April 1, 2010...

, 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.

Life and career

Johnston was born at the University of Chicago Hospital on December 18, 1949, to Thomas and Alice Johnston. They originally lived in Hometown, Illinois
Hometown, Illinois
Hometown is a city in Cook County, Illinois, United States. The population was 4,467 at the 2000 census.-Geography:Hometown is located at .According to the United States Census Bureau, the city has a total area of , all of it land....

, but moved to Oak Lawn
Oak Lawn, Illinois
Oak Lawn is a village in Cook County, Illinois, United States. The population was 55,245 at the 2000 census.Oak Lawn is a suburb of the city of Chicago, located southwest of the city...

 shortly after Johnston's birth. Johnston grew up with one sister. His father worked as an engineer at a local company and his mother as a newspaper editor. Johnston often took photographs for his mother's newspaper and contributed articles to his school's newspaper. He never married.

After graduating from high school, Johnston attended the University of Illinois at Urbana-Champaign
University of Illinois at Urbana-Champaign
The University of Illinois at Urbana–Champaign is a large public research-intensive university in the state of Illinois, United States. It is the flagship campus of the University of Illinois system...

. He planned to study journalism, but became discouraged after a poor grade in a large lecture class. He was intrigued by an introductory geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 class, and changed his major. His first geologic project was a study of the Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...

 rock that forms Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

's Upper Peninsula. There he investigated the remains of an ancient volcano: a suite of metamorphosed basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

s, a gabbro
Gabbro
Gabbro refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....

ic sill
Sill (geology)
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock. The term sill is synonymous with concordant intrusive sheet...

, and volcanic roots in the form of a dioritic
Diorite
Diorite is a grey to dark grey intermediate intrusive igneous rock composed principally of plagioclase feldspar , biotite, hornblende, and/or pyroxene. It may contain small amounts of quartz, microcline and olivine. Zircon, apatite, sphene, magnetite, ilmenite and sulfides occur as accessory...

 and gabbroic intrusion. The experience planted the seed of Johnston's passion for volcanoes. After working hard to learn the subject, he graduated with "Highest Honors and Distinction" in 1971.

Johnston spent the summer after college in the San Juan volcanic field
San Juan volcanic field
The San Juan volcanic field, located in southwestern Colorado, contains two distinct phases of volcanism. The earlier volcanism is Oligocene in age, and consists of largely intermediate composition lavas and breccias. A few ash flow tuffs also constitute this phase of volcanism. Later volcanism is...

 of Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

 working with volcanologist
Volcanologist
A volcanologist is a person who studies the formation of volcanoes, and their current and historic eruptions. Volcanologists frequently visit volcanoes, especially active ones, to observe volcanic eruptions, collect eruptive products including tephra , rock and lava samples...

 Pete Lipman in his study of two extinct caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...

s. This work became the inspiration for the first phase of his graduate work at the University of Washington
University of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...

 in Seattle, in which he focused on the Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

 Cimarron andesitic
Andesite
Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...

 volcanic complex in the western San Juans. Johnston's reconstruction of the eruptive history of the extinct volcanoes prepared him to study active volcanoes. Johnston's first experience with active volcanoes was a geophysical
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...

 survey of Mount Augustine in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 in 1975. When Mount Augustine erupted in 1976, Johnston raced back to Alaska, shunting his former work on the Cimmaron Volcano into a master's thesis
Master's degree
A master's is an academic degree granted to individuals who have undergone study demonstrating a mastery or high-order overview of a specific field of study or area of professional practice...

, and making Mount Augustine the focus of his Ph.D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...

 work. He graduated in 1978 with his Ph.D., having shown that (1) the emplacement mechanism of the pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...

s had changed over time, as they became less pumaceous
Pumice
Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...

, (2) the magmas contained high quantities of volatile water, chlorine, and sulfur, and (3) underground mixing of the felsic
Felsic
The word "felsic" is a term used in geology to refer to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium....

 (silicic) magmas with less-viscous mafic
Mafic
Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron; the term is a portmanteau of the words "magnesium" and "ferric". Most mafic minerals are dark in color and the relative density is greater than 3. Common rock-forming mafic minerals include olivine,...

 (basaltic) magmas could have triggered eruptions. Mount Augustine was also the site of an early near-disaster for Johnston, when he became trapped on the mountain during an eruption after high winds grounded the first two evacuation aircraft.

During the summers of 1978 and 1979, Johnston led studies of the ash-flow sheet emplaced in the 1912 eruption of Mount Katmai
Mount Katmai
Mount Katmai is a large stratovolcano on the Alaska Peninsula in southern Alaska, located within Katmai National Park and Preserve. It is about in diameter with a central lake-filled caldera about 3 by 2 mi in area, formed during the Novarupta eruption of 1912. The caldera rim reaches a...

 in the Valley of Ten Thousand Smokes
Valley of Ten Thousand Smokes
The Valley of Ten Thousand Smokes is a valley within Katmai National Park and Preserve in Alaska which is filled with ash flow from the eruption of Novarupta on June 6–8, 1912. Following the eruption, thousands of fumaroles vented steam from the ash. Robert F...

. The gas
Volcanic gas
|250px|thumb|right|Image of the [[rhyolitic]] [[lava dome]] of [[Chaitén Volcano]] during its 2008-2010 eruption.Volcanic gases include a variety of substances given off by active volcanoes...

 phase is extremely important in propelling volcanic eruptions. Because of this, Johnston mastered the many techniques required to analyze glass
Melt Inclusions
Melt inclusions are small parcels or "blobs" of molten rock that are trapped within crystals that grow in the magmas that form igneous rocks. In many respects they are analogous to fluid inclusions. Melt inclusions are generally small - most are less than 100 micrometres across...

-vapor inclusions
Fluid inclusions
thumb|250px|Trapped in a time capsule the same size as the diameter of a human hair, the ore-forming liquid in this inclusion was so hot and contained so much dissolved solids that when it cooled, crystals of halite, sylvite, gypsum, and hematite formed. As the samples cooled, the fluid shrank more...

 in phenocryst
Phenocryst
thumb|right|300px|[[Granite]]s often have large [[feldspar|feldspatic]] phenocrysts. This granite, from the [[Switzerland|Swiss]] side of the [[Mont Blanc]] massif, has large white [[plagioclase]] phenocrysts, [[triclinic]] [[mineral]]s that give [[trapezium|trapezoid]] shapes when cut through)...

s embedded in lavas, which provide information about gases present during past eruptions. His work at Mount Katmai and other volcanoes in the Valley of Ten Thousand Smokes paved the way for his career, and his "agility, nerve, patience, and determination around the jet-like summit fumaroles in the crater of Mt. Mageik
Mount Mageik
Mount Mageik is a stratovolcano on the Alaska Peninsula. It has no confirmed historical eruptions , but its youngest eruptive products are apparently Holocene in age...

" impressed his colleagues.

Later in 1978, Johnston joined the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

 (USGS), where he monitored volcanic emission levels in the Cascades and Aleutian Arc
Aleutian Arc
The Aleutian Arc is a large volcanic arc in the U.S. state of Alaska. It consists of a number of active and dormant volcanoes that have formed as a result of subduction along the Aleutian Trench...

. There he helped to strengthen the theory that eruptions can be predicted, to some degree, by changes in the makeup of volcanic gas
Volcanic gas
|250px|thumb|right|Image of the [[rhyolitic]] [[lava dome]] of [[Chaitén Volcano]] during its 2008-2010 eruption.Volcanic gases include a variety of substances given off by active volcanoes...

es. Fellow volcanologist Wes Hildreth said of Johnston, "I think Dave's dearest hope was that systematic monitoring of fumarolic
Fumarole
A fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...

 emissions might permit detection of changes characteristically precursory to eruptions ... Dave wanted to formulate a general model for the behavior of magmatic volatiles prior to explosive outbursts and to develop a corollary rationale for the evaluation of hazards." During this time, Johnston continued to visit Mount Augustine every summer and also assessed the geothermal energy potential of the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...

 and Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

. In the last year of his life, Johnston developed an interest in the health, agricultural, and environmental effects of both volcanic and anthropogenic emissions to the atmosphere.

Johnston was based at the Menlo Park, California
Menlo Park, California
Menlo Park, California is a city at the eastern edge of San Mateo County, in the San Francisco Bay Area of California, in the United States. It is bordered by San Francisco Bay on the north and east; East Palo Alto, Palo Alto, and Stanford to the south; Atherton, North Fair Oaks, and Redwood City...

, branch of the USGS, but his work on volcanoes took him all over the Pacific Northwest region. When the first earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

s shook Mount St. Helens on March 16, 1980, Johnston was nearby at the University of Washington
University of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...

, where he had pursued his doctorate. Intrigued by the possible advent of an eruption, Johnston contacted Stephen Malone, a professor of geology at the university. Malone had been his mentor when Johnston had worked at the San Juan complex in Colorado, and Johnston admired his work. Malone stated that he "put him to work" almost instantly, allowing Johnston to escort interested reporters to a place near the volcano. Johnston was the first geologist on the volcano, and soon became a leader within the USGS team, taking charge of monitoring of volcanic gas emissions.

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. After March 25, seismic activity drastically increased. By March 24, volcanologists at the USGS—including Johnston—became more confident that the seismic activity was a sign of an impending eruption. 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
Phreatic eruption
A phreatic eruption, also called a phreatic explosion or ultravulcanian eruption, occurs when rising magma makes contact with ground or surface water. The extreme temperature of the magma causes near-instantaneous evaporation to steam, resulting in an explosion of steam, water, ash, rock, and...

 took place, ejecting a plume of ash nearly 7000 feet (2,134 m) 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
Tephra
200px|thumb|right|Tephra horizons in south-central [[Iceland]]. The thick and light coloured layer at center of the photo is [[rhyolitic]] tephra from [[Hekla]]....

. With each new eruption, the plumes of steam and ash from the volcano rose, eventually climbing to 20000 feet (6,096 m). By late March, the volcano was erupting up to 100 times per day. 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.

On April 17, a bulge was discovered on the mountain's north flank, suggesting that Mount St. Helens could produce a lateral blast. Johnston was one of few people who believed this, along with a professor of geology at a Tacoma community college, Jack Hyde. Observing that Mount St. Helens did not possess visible vents, Hyde suggested that pressure would increase until the mountain exploded. Because Hyde was not a part of the USGS or in a position of responsibility, his opinion was generally dismissed. However, both were to be proven correct. Rising magma
Magma
Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 under Mount St. Helens had veered off to the north flank, creating a growing bulge on the surface.

Final signs and primary blast

Given the increasing seismic and volcanic activity, Johnston and the other volcanologists working for the USGS in its Vancouver branch prepared to observe any impending eruption. Geologist Don Swanson and others placed reflectors on and around the growing domes, and established the Coldwater I and II observation posts to use laser ranging to measure how the distances to these reflectors changed over time as the domes deformed. Coldwater II, where Johnston died, was located just 6 miles (10 km) north of the mountain. To the astonishment of the USGS geologists, the bulge was growing at a rate of 5 to 8 feet (1.5 to 2.4 meters) per day.
Tiltmeter
Tiltmeter
A tiltmeter is an instrument designed to measure very small changes from the horizontal level, either on the ground or in structures. A similar term, in less common usage, is the inclinometer...

s installed on the volcano's north side displayed a northwest trending tilt for that side of the mountain, and a southwest trending tilt was observed on the south side. Worried that the amount of pressure on the magma underground was increasing, scientists analyzed gases by the crater, and found high traces of sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...

. After this discovery, they began to regularly check the fumarolic activity and monitor the volcano for dramatic changes, but none were observed. Disheartened, they instead opted to study the growing bulge and the threat an avalanche could have for humans relatively near the volcano. An evaluation of the threat was carried out, concluding that a landslide or avalanche in the Toutle River
Toutle River
The Toutle River is a river in southwestern Washington State, in the Pacific Northwest region of the United States. It rises in two forks on the flanks of Mount St. Helens and joins the Cowlitz River near Castle Rock.-Eruption of Mount St. Helens:...

 could spawn lahar
Lahar
A lahar is a type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris, and water. The material flows down from a volcano, typically along a river valley. The term is a shortened version of "berlahar" which originated in the Javanese language of...

s, or mudflows, downstream.

At that point, the previously consistent phreatic
Phreatic
The term phreatic is used in Earth sciences to refer to matters relating to ground water below the water table . The term 'phreatic surface' indicates the location where the pore water pressure is under atmospheric conditions...

 activity had become intermittent. Between May 10 and May 17, the only change occurred on the volcano's north flank, as the bulge increased in size. On May 16 and 17, the mountain stopped its phreatic eruptions completely.

The active Mount St. Helens was extremely different from its dormant form, now featuring an enormous bulge and several craters. In the week preceding the eruption, cracks formed in the north sector of the volcano's summit, indicating a movement of magma from the bulge and towards the caldera.

At 8:32 a.m. local time the next day (18 May), an earthquake measuring magnitude 5.1 on the Richter scale rocked the area, triggering the landslide that started the main eruption. In a matter of seconds, vibrations from the earthquake loosened 2.7 cubic kilometre (0.647764448231574 cu mi) of rock on the mountain's north face and summit, creating a massive landslide. With the loss of the confining pressure of the overlying rock, the caldera of Mount St. Helens began to rapidly emit steam and other volcanic gases. A few seconds later, it erupted laterally, sending swift pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...

s down its flanks at near supersonic
Supersonic
Supersonic speed is a rate of travel of an object that exceeds the speed of sound . For objects traveling in dry air of a temperature of 20 °C this speed is approximately 343 m/s, 1,125 ft/s, 768 mph or 1,235 km/h. Speeds greater than five times the speed of sound are often...

 speeds. These flows were later joined by lahars. Before being struck by a series of flows that at their fastest would have taken less than a minute to reach his position, Johnston managed to radio "Vancouver! Vancouver! This is it!" to his USGS co-workers. Seconds later, the signal from the radio went silent. Initially, there was some debate as to whether Johnston had survived; records soon showed a radio message from fellow eruption victim and amateur radio operator Gerry Martin, located near the Coldwater peak and further north of Johnston's position, reporting his sighting of the eruption enveloping the Coldwater II observation post. As the blast overwhelmed Johnston's post, Martin declared solemnly, "Gentlemen, the uh, camper and the car sitting over to the south of me is covered. It's gonna get me, too. I can't get out of here ..." before his radio, too, went silent.

The extent, speed and direction of the avalanche and pyroclastic flows that overwhelmed Johnston, Martin, and others were later described in detail in a paper titled 'Chronology and Character of the 18 May 1980 Explosive Eruptions of Mount St. Helens', published in 1984 in a collection published by the National Research Council
United States National Research Council
The National Research Council of the USA is the working arm of the United States National Academies, carrying out most of the studies done in their names.The National Academies include:* National Academy of Sciences...

's Geophysics Study Committee. In this paper, the authors examined photographs and satellite images of the eruption to construct a chronology and description of the first few minutes. Included in the paper is figure 10.3, a series of timed photographs taken from Mount Adams
Mount Adams (Washington)
Mount Adams is a potentially activestratovolcano in the Cascade Range and the second-highest mountain in the U.S. state of Washington.Adams is a member of the Cascade Volcanic Arc, and is one of the arc's largest volcanoes,...

, 33 miles (53.1 km) east of Mount St. Helens. These six photographs, taken sideways on to the lateral blast, vividly show the extent and size of the avalanche and flows as they reached northwards over and beyond Johnston's position. Figure 10.7 from the same paper is an overhead diagram showing the position of the pyroclastic surge front at half-minute intervals, with the positions of Johnston (Coldwater II) and Martin included.

The eruption was heard hundreds of miles away, but some of those who survived the eruption declared that the landslide and pyroclastic flows were silent as they raced down the mountain. Krau Kilpatrick, an employee of the United States Forest Service
United States Forest Service
The United States Forest Service is an agency of the United States Department of Agriculture that administers the nation's 155 national forests and 20 national grasslands, which encompass...

, recalled, "There was no sound to it, not a sound. It was like a silent movie and we were all in it." The reason for this discrepancy is a "quiet zone", created as a result of the motion and temperature of air and, to a lesser extent, upon local topography.

Famous for telling reporters that being on the mountain was like "standing next to a dynamite keg and the fuse is lit", Johnston had been among the first volcanologists at the volcano when eruptive signs appeared, and shortly after was named the head of volcanic gas monitoring. Though a careful analyst, Johnston strongly believed that scientists needed to take this risk for themselves in order to prevent civilian deaths, and therefore chose to partake in dangerous on-site monitoring. He and several other volcanologists prevented people from being near the volcano during the few months of pre-eruptive activity, and successfully fought pressure to re-open the area. Their work kept the death toll at a few tens of individuals, instead of the thousands who possibly could have died had the region not been closed off. Johnston supported the lateral blast theory: he believed the explosive eruption would be ejected sideways out of the volcano, not upward. He also believed that the eruption would originate from the bulge. Because of this, he was more aware than most of the threat of a north-directed eruption.

USGS team and rescue efforts

Many USGS scientists worked on the team monitoring the volcano, but it was graduate student Harry Glicken
Harry Glicken
Harry Glicken was a volcanologist who was killed on 3 June 1991 by a pyroclastic flow on Mount Unzen in Japan. Also killed were forty-two other scientists and journalists, including volcanologists Katia and Maurice Krafft....

 who had been manning the Coldwater II observation post for the two and a half weeks immediately preceding the eruption. The evening before the eruption he was scheduled to be relieved by USGS geologist Don Swanson in order to visit the graduate school at the University of California. Swanson, however, wanted to meet with a German graduate student who was returning to Germany on May 18. Two days before the eruption, Swanson ran into Johnston in the hallway and asked him to take his place. Johnston hesitantly agreed to man the base for one day. That Saturday, the day before the eruption took place, Johnston ascended the mountain and went on a patrol of the volcano with geologist Carolyn Driedger. Tremors shook the mountain. Driedger was supposed to camp on one of the ridges overlooking the volcano that night, but Johnston told her to head home and said that he would stay on the volcano alone. While at Coldwater II, Johnston was to observe the volcano for any further signs of an eruption. Just prior to his departure, at 7 p.m. on the evening of May 17, 13½ hours before the eruption, Glicken took a photograph of Johnston sitting by the observation post trailer with a notebook on his lap, smiling.

The following morning, May 18, at , the volcano erupted. Immediately, rescue workers were dispatched to the area. The official USGS pilot, Lon Stickney, who had been flying the scientists to the mountain, conducted the first rescue attempt. He flew his helicopter over the scarred remains of trees, valleys, and the Coldwater II observation post ridge, where he saw bare rock and uprooted trees. Because he saw no sign of Johnston's trailer, Stickney began to panic, becoming "emotionally distraught".

Frantic and guilt-stricken, Harry Glicken convinced three separate helicopter pilots to take him up on flights over the devastated area in a rescue attempt, but the eruption had so changed the landscape that they were unable to locate any sign of the Coldwater II observation post, which had been swept away and buried in the blast. He and the helicopter crew did manage to find a car with people in it at a logging camp, but when they landed to attempt an evacuation, skin fell off the dead victims' hands. Shortly after the eruption, Don Swanson found Johnston's backpack and parka buried in the rubble, but he hid the discovery from all but a few people for fear that scavengers (who were already removing and selling souvenirs of victims of the volcano) would find and remove his friend's body or belongings. In 1993, while building a 9 miles (14.5 km) extension of Washington State Route 504 (also called "Spirit Lake Memorial Highway") to lead to the Johnston Ridge Observatory, construction workers discovered pieces of Johnston's trailer. His body, however, was not found and has never been recovered.

Consequences and response

The public was shocked by the extent of the eruption, which had lowered the elevation of the summit by 1313 feet (400 m), destroyed 230 square miles (596 km²) of woodland, and spread ash into other states. The lateral blast that killed Johnston started at 220 miles per hour (354 km/h) and accelerated to 670 miles per hour (1,078 km/h). Even USGS scientists were awed. With a Volcanic Explosivity Index
Volcanic Explosivity Index
The Volcanic Explosivity Index was devised by Chris Newhall of the U.S. Geological Survey and Stephen Self at the University of Hawaii in 1982 to provide a relative measure of the explosiveness of volcanic eruptions....

 value of 5, the eruption was catastrophic. More than 50 people were killed or missing, including Johnston, mountain resident Harry Randall Truman, and National Geographic photographer Reid Blackburn
Reid Blackburn
Reid Turner Blackburn was a photographer killed in the 1980 volcanic eruption of Mount St. Helens. Blackburn was a photojournalist covering the eruption for a local newspaper—the Vancouver, Washington Columbian—as well as National Geographic magazine and the United States Geological Survey when he...

.

The disaster was the deadliest and most destructive volcanic eruption in the history of the United States of America. A total of 57 people are known to have died, and more were left homeless when the ash falls and pyroclastic flows destroyed or buried 200 houses. In addition to the human fatalities, thousands of animals perished. The official estimate from the USGS was 7,000 game animals, salmon fingerlings, and 40,000 salmon.

Two years after the eruption, the United States government set aside 110000 acres (445.2 km²) of land for the Mount St. Helens National Volcanic Monument
Mount St. Helens National Volcanic Monument
Mount St. Helens National Volcanic Monument is a U.S. National Monument that includes the area around Mount St. Helens in Washington. It was established on August 27, 1982 by U.S. President Ronald Reagan following the 1980 eruption of Mount St. Helens. The 110,000 acre National Volcanic...

. This protected area, which includes the Johnston Ridge Observatory and several other research and visitor centers, serves as an area for scientific research, tourism, and education.

Scientific

Johnston, known to his friends as Dave, was commemorated by both his fellow scientists and by the government. Known for his diligent and particular nature, he was called "an exemplary scientist" by a USGS dedication paper, which also described him as "unaffectedly genuine, with an infectious curiosity and enthusiasm". He was quick to "dissipate cynicism" and believed that "careful evaluation and interpretation" was the best approach to his work. An obituary notice for Johnston stated that at the time of his death he had been "among the leading young volcanologists in the world" and that his "enthusiasm and warmth" would be "missed at least as much as his scientific strength". Co-worker Andrew Alden states that Johnston had great potential, declaring that he "had many friends and a bright future". Following the eruption, Harry Glicken and other geologists at the USGS dedicated their work to Johnston.

Because Johnston was believed to be safe at the Coldwater II observation post, the fact that he died shocked his friends and co-workers alike. However, most of his colleagues and family asserted that Johnston died "doing what he wanted to do." His mother stated in an interview shortly after the eruption, "Not many people get to do what they really want to do in this world, but our son did. ... He would tell us he may never get rich but he was doing what he wanted. He wanted to be near if the eruption came. In a phone call on Mother's Day, he told us it's a sight very few geologists get to see." Dr. Stephen Malone agreed that Johnston died doing what he loved, and stated that he "was very good at his work".

Johnston's role in the study of the volcano in the weeks leading up to the eruption was acknowledged in 1981 in a chronology of the eruption, published as part of the USGS report titled 'The 1980 Eruptions of Mount St. Helens, Washington':
Since Johnston's death, his field of volcanic eruption prediction has advanced significantly, and volcanologists are now able to predict eruptions based on a number of precursors that become apparent between days and months in advance. Geologists can now identify characteristic patterns in seismic waves that indicate particular magmatic activity. In particular, volcanologists have used deep, long-period earthquakes that indicate that magma is rising through the crust. They can also use carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 emission as a proxy for magma supply rate. Measurements of surface deformation due to magmatic intrusions, like those that were conducted by Johnston and the other USGS scientists at the Coldwater I and II outposts, have advanced in scale and precision. Ground deformation monitoring networks around volcanoes now consist of InSAR
Insar
Insar is a town and the administrative center of Insarsky District of the Republic of Mordovia, Russia, located southwest of Saransk at the confluence of the Issa and Insarka Rivers. Population:...

 (interferometry), surveys of networks of GPS monuments, microgravity surveys in which scientists measure the change in gravitational potential or acceleration
Gravitational acceleration
In physics, gravitational acceleration is the acceleration on an object caused by gravity. Neglecting friction such as air resistance, all small bodies accelerate in a gravitational field at the same rate relative to the center of mass....

 because of the intruding magma and resulting deformation, strain meters, and tiltmeters. Though there is still work to be done, this combination of approaches has greatly improved scientists' abilities to forecast volcanic eruptions.

Despite the deaths of other volcanologists in later eruptions at Mount Unzen
Mount Unzen
is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki Prefecture, on the island of Kyūshū, Japan’s southernmost main island....

 and Galeras
Galeras
Galeras is an Andean stratovolcano in the Colombian department of Nariño, near the departmental capital Pasto. Its summit rises above sea level. It has erupted frequently since the Spanish conquest, with its first historical eruption being recorded on December 7, 1580...

, prediction methods similar to Johnston's allowed scientists to convince residents of settlements near the Mount Pinatubo
Mount Pinatubo
Mount Pinatubo is an active stratovolcano located on the island of Luzon, near the tripoint of the Philippine provinces of Zambales, Tarlac, and Pampanga. It is located in the Tri-Cabusilan Mountain range separating the west coast of Luzon from the central plains, and is west of the dormant and...

 volcano to evacuate, preventing thousands of deaths. In addition to his work, Johnston himself has become part of the history of volcanic eruptions. With Harry Glicken, he is one of two volcanologists from the United States to die in a volcanic eruption. Glicken was being mentored by Johnston, who relieved Glicken of his watch at the Coldwater II observation post 13 hours before Mount St. Helens erupted. Glicken died in 1991, eleven years later, when a pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...

 overran him and several others at Mount Unzen
Mount Unzen
is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki Prefecture, on the island of Kyūshū, Japan’s southernmost main island....

 in Japan.

Commemoration

Early acts of commemoration included two trees that were planted in Tel Aviv, Israel, and the renaming of a community center in Johnston's hometown as the "Johnston Center". These actions were reported in newspapers during the first anniversary of the eruption in May 1981.

On the second anniversary of the eruption, the USGS office in Vancouver (which had been permanently established following the 1980 eruption) was renamed the David A. Johnston Cascades Volcano Observatory
Cascades Volcano Observatory
The David A. Johnston Cascades Volcano Observatory is the volcano observatory that monitors volcanoes in the Cascade Range. It is part of the United States Geological Survey, a scientific agency of the United States government. It is located in Vancouver, Washington in the Portland, Oregon...

 (CVO) in his memory. This volcano observatory is the one most responsible for monitoring Mount St. Helens, and helped to predict all of the volcano's eruptions between 1980 and 1985. In a 2005 open day, the lobby area of the CVO included a display and painting commemorating Johnston.

Johnston's connections with the University of Washington
University of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...

 (where he had carried out his masters and doctoral research) are remembered by a memorial fund that established an endowed graduate-level fellowship within what is now the department of Earth and Space Sciences. By the time of the first anniversary of his death, the fund had exceeded $
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

30,000. Known as the 'David A. Johnston Memorial Fellowship for Research Excellence', a number of awards of this fellowship have been made over the years since it was launched.

Following the eruption, the area where the Coldwater II observation post had been was sectioned off. Eventually, an observatory was built in the area in Johnston's name, and opened in 1997. Located just over 5 miles (8 km) from the north flank of Mount St. Helens, the Johnston Ridge Observatory (JRO) allows the public to admire the open crater, new activity, and the creations of the 1980 eruption, including an extensive basalt field. Part of the Mount St. Helens National Volcanic Monument, the JRO was constructed for , equipped with monitoring equipment. Visited by thousands of tourists annually, it also includes tours, a theater, and an exhibit hall.

There are several public memorials where Johnston's name is inscribed in a list of those known to have died in the eruption. These memorials include a large curved granite monument at an outside viewing area at the Johnston Ridge Observatory, which opened in 1997, and a plaque at the Hoffstadt Bluffs Visitor Center, which was unveiled in a memorial grove in May 2000.

Depictions

There have been several tellings of Johnston's story in documentaries, films and docudrama
Docudrama
In film, television programming and staged theatre, docudrama is a documentary-style genre that features dramatized re-enactments of actual historical events. As a neologism, the term is often confused with docufiction....

s about the eruption. Documentaries such as The Eruption of Mount St. Helens!
The Eruption of Mount St. Helens!
The Eruption of Mount St. Helens! is a 1980 short documentary film directed by George Casey. It was nominated for an Academy Award for Best Documentary Short....

(1980) appeared the same year, while a movie was filmed in the year following the eruption and released to coincide with the first anniversary. The story of Mount St. Helens and Johnston continues to be told in documentaries and reconstructions several decades after the eruption took place.

In the 1981 film St. Helens, actor David Huffman
David Huffman
David Huffman was a longtime character actor with many television, film and stage credits. He was married to award winning casting director Phyllis Huffman until he was murdered in 1985.-Murder:...

 starred as a renamed Johnston (David Jackson). Controversially, Huffman's character became involved in a love affair and was killed by the blast while on top of the mountain. Johnston's parents criticized the production of the film, arguing that it possessed not "an ounce of David in it" and portrayed "him as a daredevil rather than a careful scientist". They threatened to sue over the fact that they felt their son's memory had been contaminated. Johnston's mother stated that the film had changed many true aspects of the eruption, and depicted her son as "a rebel" with "a history of disciplinary trouble".

Prior to the film's release during the one-year anniversary of the eruption, 36 scientists who knew Johnston signed a letter of protest. They wrote that, "Dave's life was too meritorious to require fictional embellishments," and that, "Dave was a superbly conscientious and creative scientist." Don Swanson, a USGS geologist who was Johnston's friend and who, due to other commitments, had convinced Johnston to take his place at the Coldwater II observation post on the day of the eruption, believed that a movie based on Johnston's true life and exploits would have been a hit because of his friend's character.

Several documentaries and docudramas have covered the history of the eruption, including archive footage and dramatisations of Johnston's story. These include Up From the Ashes (1990) by KOMO-TV
KOMO-TV
KOMO-TV, virtual channel 4, is a television station in Seattle, Washington. It is an affiliate of ABC and broadcasts on digital channel 38. KOMO-TV is the flagship station of Fisher Communications, and its studios and offices are co-located with sister radio stations KOMO , KVI , and KPLZ-FM ...

, an episode of the 2005 second series of Seconds From Disaster
Seconds From Disaster
-By original broadcast date:National Geographic Channel has broadcast many episodes under multiple titles. The title currently or most recently listed on the NGC Calendar is shown first...

broadcast by the National Geographic Channel
National Geographic Channel
National Geographic Channel, also commercially abbreviated and trademarked as Nat Geo, is a subscription television channel that airs non-fiction television programs produced by the National Geographic Society. Like History and the Discovery Channel, the channel features documentaries with factual...

, and an episode of the 2006 series Surviving Disaster
Surviving Disaster
Surviving Disaster is a BBC, Discovery Channel, and ProSieben co-production documentary series about disasters in the 20th century, starring people who survived them. It was produced in association with France 5....

, broadcast on the BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...

 and Discovery Channel
Discovery Channel
Discovery Channel is an American satellite and cable specialty channel , founded by John Hendricks and distributed by Discovery Communications. It is a publicly traded company run by CEO David Zaslav...

.

External links

  • David A. Johnston (United States Geological Survey obituary, hosted by the Cascades Volcano Observatory)
  • David Alexander Johnston – memoriam article by Wes Hildreth – includes 1978 photograph of Johnston (USGS Geological Survey Circular 838, hosted by the US National Park Service)
  • David Johnston – memorial page that includes photographs of Johnston following his arrival at the volcano (St. Helens Hero website)
  • This is it – 1995 local newspaper retrospective on Johnston (St. Helens Hero website)
  • The Victims of the Eruption – memorial page that includes a photograph of the Hoffstadt Bluffs memorial plaque (The many faces of Mount St. Helens website)
  • Mount St. Helens - Victims – map that shows the position of Johnston and the others killed by the eruption (The Daily News, TDN.com)
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