How much ash was there from the May 18, 1980 eruption of Mount St. Helens?
During the 9 hours of vigorous eruptive activity on May 18, 1980, about 540 million tons of ash from Mount St. Helens fell over an area of more than 22,000 square miles. The total volume of the ash before its compaction by rainfall was about 0.3 cubic mile, equivalent to an area the size of a football field piled about 150 miles high with fluffy ash.
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Ever Vigilant: USGS Marks the 37th Anniversary of Mount St. Helen's Eruption and the 35th Anniversary of the Cascades Volcano Observatory
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.
EarthWord–Phreatic Eruption
This EarthWord is straight up steampunk...
EarthWord–Lahar
Which sounds more dangerous, lava or mud? The answer may surprise you...
May is Volcano Preparedness Month in Washington State
May is Volcano Preparedness Month in Washington, providing residents an opportunity to become more familiar with volcano hazards in their communities and learn about steps they can take to reduce potential impacts.
EarthWord–Subduction
It’s not flirting for submarines, but this week’s EarthWord does feature the ocean...
EarthWord–Tephra
Look! In the sky! It’s a bird, it’s a plane! Wait, run, it’s this week’s EarthWord!
PubTalk 2/2018 — USGS Cascades Volcano Observatory
Title: The USGS Cascades Volcano Observatory - Research, monitoring, and the science of preparing society for low-probability, high-consequence events
- Volcanoes in the Cascade Range erupt twice per century on average, with eruptions often lasting for years.
- Although eruptions are generally not as high-consequence as large earthquakes, they are still
Forecasting Ashfall Impacts from a Yellowstone Supereruption
- Yellowstone is one of a few dozen volcanoes on earth capable of "supereruptions" that expel more than 1,000 cubic km of ash and debris.
- The plumes from such eruptions can rise 30 to 50 km into the atmosphere, three to five times as high as most jets fly.
- Yellowstone has produced three supereruptions in the past 2.1 million years. The most recent was
Mount St. Helens before and after 1980 eruption
Left: 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.
Right: Mount St. Helens soon after the May 18, 1980 eruption, as viewed from Johnston's Ridge.
Volcano Hazards
The United States has 169 active volcanoes. More than half of them could erupt explosively, sending ash up to 20,000 or 30,000 feet where commercial air traffic flies. USGS scientists are working to improve our understanding of volcano hazards to help protect communities and reduce the risks.
Video Sections:
- Volcanoes: Monitoring Volcanoes
Volcano Web Shorts 2: Debris Flows
Debris flows are hazardous flows of rock, sediment and water that surge down mountain slopes and into adjacent valleys. Hydrologist Richard Iverson describes the nature of debris-flow research and explains how debris flow experiments are conducted at the USGS Debris Flow Flume, west of Eugene, Oregon. Spectacular debris flow footage, recorded by Franck Lavigne of the
...Volcano Web Shorts 4 - Instruments
USGS technologist Rick LaHusen describes how the development and deployment of instruments plays a crucial role in mitigating volcanic hazards.
Volcano Web Shorts 5 - Volcanic Ash Impacts
Volcanic ash is geographically the most widespread of all volcanic hazards. USGS geologist Larry Mastin describes how volcanic ash can disrupt lives many thousands of miles from an erupting volcano. The development of ash cloud models and ash cloud disruption to air traffic is highlighted.
Mount St. Helens: May 18, 1980
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.
Mount St. Helens: A Catalyst for Change
The May 18, 1980 eruption of Mount St. Helens triggered a growth in volcano science and volcano monitoring. Five USGS volcano observatories have been established since the eruption. With new technologies and improved awareness of volcanic hazards USGS scientists are helping save lives and property across the planet.
Mount St. Helens 2004-2008 Eruption: A Volcano Reawakens
Mount St. Helens reawakened in late September 2004. Small magnitude earthquakes beneath the 1980-1986 lava dome increased in frequency and size, and a growing welt formed on the southeast margin of the previous lava dome and nearby portions of Crater Glacier. On October 1, 2004, the first of several explosions shot a plume of volcanic ash and gases from a vent on the
...Mount St. Helens eruption highlights: September 2004 - May 2005
Compilation video of significant events from the dome-building eruption at Mount St. Helens, from October 1, 2004 to March 15, 2005, including steam and ash eruptions, growth of lava spines, helicopter deployment of monitoring equipment, collection of lava samples, and FLIR thermal imaging of rock collapse on lava dome.
- Eruption of Mount St. Helens, October 1