Ever Vigilant: USGS Marks the 37th Anniversary of Mount St. Helen's Eruption and the 35th Anniversary of the Cascades Volcano Observatory

Release Date:

Today, in 1980, Mount St. Helens unleashed the most devastating eruption in U.S. history. Two years later, USGS founded the Cascades Volcano Observatory to monitor Mount St. Helens and all the Cascades Volcanoes.

Aerial photo of Mount St. Helens volcano, pre-1980 eruption
Before the eruption of May 18, 1980, Mount St. Helens' elevation was 2,950 m (9,677 ft). View from the west, Mount Adams in distance. S. Fork Toutle River is valley in center of photo.Mount Adams elevation is 3,745 m (12, 286 ft). Mount St. Helens was the smallest of five major volcanic peaks in Washington State.(Credit: Rick Hoblitt, U.S. Geological Survey Cascades Volcano Observatory. Public domain.)

The Nation’s Wake-up Call

On March 20, 1980, a strong earthquake shook  the slopes of a picture-perfect, snow-capped mountain in the Cascades Range. The earthquake was recorded by seismometers installed by a group of University of Washington and USGS scientists, who were studying geothermal resource potential in the area. The earthquake was the first of an intense sequence of earthquakes that were unusual for the Pacific Northwest. Their location directly beneath the volcano was immediately recognized as a possible symptom of an impending eruption. If the mountain did become active, what would happen? Although no one knew it then, that was the beginning of the Nation’s wake-up call to the presence of true volcanic hazard in the Pacific Northwest.

The mountain is Mount St. Helens. As the world later watched, that strong earthquake was followed by many earthquakes as magma forced its way upwards , bulging the north flank of the volcano and forging a path to the surface with every earthquake and small steam-and-ash explosion. Less than two months later, the mountain gave way with a tremendous landslide and lateral blast, resulting in the loss of 57 lives-including USGS scientist David Johnston-and property damage and destruction totaling over a billion dollars.

Volcano erupting and spewing a huge cloud of rock and ash into the sky.
On Sunday, May 18, 1980 at 8:32 a.m., the bulging north flank of Mount St. Helens slid away in a massive landslide -- the largest in recorded history. Seconds later, the uncorked volcano exploded and blasted rocks northward across forest ridges and valleys, destroying everything in its path within minutes.(Public domain.)

The Mount St. Helens eruption in 1980 ranks among the most significant geologic events of the 20th century for both the United States and the world. Occurring near populated areas and in the age of television, people throughout the United States and around the globe were captivated at images of the volcano’s catastrophic eruption, the devastation, and the stories of impacted lives.

An Especially Dangerous Volcano

In the mid-1970s, USGS geologists Dwight R. Crandell, Donal R. Mullineaux and others roved the slopes of Mount St. Helens, investigating the lava flows and layers of ash and pumice that revealed a story of a frequently active and at times highly explosive volcano. A hazards report prepared in 1978 suggested Mount St. Helens could be an especially dangerous volcano because of its past behavior.

USGS scientists recount their experiences before, during and after the May 18, 1980 eruption of Mount St. Helens. Loss of their colleague David A. Johnston and 56 others in the eruption cast a pall over one of the most dramatic geologic moments in American history. Stephen M. Wessells, U.S. Geological Survey(Public domain.)

In 1980, as earthquakes intensified, USGS scientists from Hawaii, Alaska, California and Colorado descended on Mount St. Helens, joining forces with scientists at the University of Washington who had detected the initial earthquakes and sounded the early alarm.  The rate of changes at the volcano required around-the-clock work both in the field at observation posts like Coldwater I and Coldwater II, and at U.S. Forest Service headquarters in Vancouver, Washington. The media, public officials, first-responders and land managers were updated daily about events at the volcano. There was no formal Cascades Volcano Observatory and no dedicated office space. Instead, scientists staged their volcano monitoring program within an operations center established at the U.S. Forest Service headquarters in downtown Vancouver, Washington.

Image shows two scientists on the slopes of Mount St. Helens with steam rising around them
USGS geologists gathered samples by hand from vents on the dome and crater floor. Additionally, sulfur dioxide gas was measured from a specially equipped airplane before, during, and after eruptions to determine "emission rates" for the volcano.(Credit: Thomas Casadevall, USGS. Public domain.)

Just as it appeared that unrest at Mount St. Helens was diminishing, the north flank of the volcano failed. On May 18, 1980, the bulge slid into the valley and uncorked a catastrophic lateral blast. In total, the top 1,300 feet of the mountain was removed. At a speed of more than 300 mph, the blast flattened 230 square miles and reached 17 miles northwest of the crater. Lahars (volcanic mudflows) inundated valley floors and carried sediment as far as Columbia River. Fifty-seven people, along with countless wildlife and fish populations, died in the eruption. USGS scientist David Johnston was caught up in the blast, even though he was at a distance presumed relatively safe at the time.

The Beginnings of CVO

Image shows a black and white photograph of a man in a lab coat surrounded by news media
Press conference with Donald W. Peterson, Scientist-in-Charge of the Survey Office at Vancouver. Cameras and news people in foreground. Photo by Henry Spall. Clark County, Washington. September 26, 1980. Published on p. 225, lower photo, in U.S. Geological Survey.(Public domain.)

What would the volcano do next? During the summer of 1980, explosive eruptions sent ash to nearly all four corners of Washington State and beyond. Within the crater, a new dome began forming, producing a new set of hazards stemming from the possibility of dome collapse. The USGS took on the role of lead Federal agency responsible for providing reliable and timely warnings of volcanic hazards to state and local authorities, eventually moving out of the joint field office operated with the U.S. Forest Service and establishing a permanent regional office at Vancouver, Washington, an office that was officially dedicated on May 18, 1982.  The Cascades Volcano Observatory (or CVO), as it was named, was dedicated in David Johnston’s memory and sought to ensure that future volcanic activity in the Cascades Range would come as no surprise to the region and that people would have as much time as possible to prepare.

Image shows several people eating lunch on a sidewalk outside a building
USGS field office in downtown Vancouver, Washington in 1981, prior to the official designation of the Cascades Volcano Observatory.(Public domain.)

Throughout the next 35 years, the CVO has progressively expanded its monitoring and study of other volcanoes of the Cascades Range.  Nevertheless, Mount St. Helens has continued to be a focus of the new observatory, as eruptions continued throughout much of the 1980s and again in 2004-2008 during a renewed period of dome building eruptions. CVO has maintained a watchful eye throughout all of these eruptions and kept local communities apprised of the volcano’s activities.

CVO Today-Ever Watchful

Image shows a group of people standing in front of a brick wall
Staff of CVO. (Public domain.)

Today, the USGS Cascades Volcano Observatory continues its mission of keeping a watchful eye on the volcanoes of the Cascades Range. In the Pacific Northwest, the number of people at immediate risk during eruptions is greater than at any other volcanic area within the United States. Additionally, aviation air space between the Canadian border and Mount Shasta accommodates almost 2,000 flights daily. The next eruption near a Cascade volcano could upset the lives of hundreds of thousands of people and disrupt many others.

Image shows a map with potential volcano hazards to the surrounding area for Mount St. Helens
Mount St. Helens, Washington simplified hazards map showing potential impact area for ground-based hazards during a volcanic event. More simplified volcano hazard maps for the other Cascades Volcanoes can be found here.(Public domain.)

Fortunately, volcanoes tend to give warning signs that they’re getting ready to erupt, and CVO scientists keep ever-vigilant to make sure that residents of the Pacific Northwest have as much warning as possible before an eruption. During the past decade at CVO, USGS and the Pacific Northwest Seismograph Network have expanded monitoring networks on Mount St. HelensMount RainierMount Hood, Three Sisters, Newberry Volcano, and Crater Lake. Although they are often located in hard-to-access places, you still might see these instruments on a volcano's slopes; please know that they are hard at work for communities downwind and downstream of the volcano.

Image shows a scientific instrument on the slopes of Mount St Helens
A survey base station is established using a RTK-GPS receiver with mobile units to collect data points in and around the crater. Information will be used to monitor surface changes, deformation, erosion and aggradation inside the crater. This type of technology is precise to the centimeter. View is to the south of Mount St. Helens, toward Crater Glacier and the lava domes. (Credit: Adam Mosbrucker, USGS. Public domain.)

CVO also coordinates with the other four USGS volcano observatories and the USGS Volcano Disaster Assistance Program to stay at the forefront of volcanic monitoring, volcano hazards assessments, and eruption forecasting. In addition, CVO keeps the public informed through outreach efforts to public officials, land-use planners, emergency response organizations, the Federal Aviation Administration, National Weather Service, and other Federal agencies, the news media, schools, and the general public. When volcanic activity increases, CVO issues advisories, warnings, and, whenever possible, specific forecasts concerning eruptions and their potential impacts.

Although the Cascade volcanoes currently slumber, it is only a matter of time before one reawakens. When that happens, CVO and its partners will be there and ready go.

Image: Seth Moran, USGS Cascades Volcano Observatory
Seth Moran, Scientist-in-Charge of the U.S. Geological Survey Cascades Volcano Observatory.(Credit: Liz Westby, USGS. Public domain.)

Scientists in Charge:

  • Don Peterson 1980 - 1983
  • Norm MacLeod 1984 - 1986
  • Don Swanson 1986 - 1989
  • Ed Wolfe 1989 - 1994
  • Dan Dzurisin 1994 - 1997
  • Willie Scott 1998 - 2003
  • Elliot Endo 2003 - 2004
  • Cynthia Gardner 2004 - 2010
  • John Ewert 2010 - 2015
  • Seth Moran - 2015 - present