Back ثوران جبل سانت هيلين سنة 1980 Arabic Изригване на Сейнт Хелънс през 1980 г. Bulgarian Ausbruch des Mount St. Helens 1980 German Έκρηξη του όρους της Αγίας Ελένης 1980 Greek Erupción del monte Santa Helena de 1980 Spanish فوران کوه سنت هلن در سال ۱۹۸۰ Persian St. Helensin purkaus 1980 Finnish Éruption du mont Saint Helens en 1980 French Letusan Gunung St. Helens 1980 ID Eruzione del monte Saint Helens del 1980 Italian
| 1980 eruption of Mt. St. Helens | |
|---|---|
 Photograph of the eruption column, May 18, 1980, taken by Austin Post | |
| Volcano | Mount St. Helens |
| Date | (climactic episode) May 18, 1980[1] |
| Type | Phreatic, Plinian, Peléan |
| Location | Skamania County, Washington, U.S. 46°12′1″N 122°11′12″W / 46.20028°N 122.18667°W |
| VEI | 5[1] |
| Impact | Approximately 57 deaths, about $1.1 billion in property damage ($3.4 billion in 2023); caused a collapse of the volcano's northern flank, deposited ash in eleven U.S. states and five Canadian provinces |
 Map of eruption deposits | |
On March 27, 1980, a series of volcanic explosions and pyroclastic flows began at Mount St. Helens in Skamania County, Washington, United States. A series of phreatic blasts occurred from the summit and escalated until a major explosive eruption took place on May 18, 1980, at 8:32 am. The eruption, which had a volcanic explosivity index of 5, was the first to occur in the contiguous United States since the much smaller 1915 eruption of Lassen Peak in California.[2] It has often been declared the most disastrous volcanic eruption in U.S. history.
The eruption was preceded by a two-month series of earthquakes and steam-venting episodes caused by an injection of magma at shallow depth below the volcano that created a large bulge and a fracture system on the mountain's north slope. An earthquake at 8:32:11 am PDT (UTC−7) on May 18, 1980,[3] caused the entire weakened north face to slide away, a sector collapse which was the largest subaerial landslide in recorded history.[4] This allowed the partly molten rock, rich in high-pressure gas and steam, to suddenly explode northward toward Spirit Lake in a hot mix of lava and pulverized older rock, overtaking the landslide. An eruption column rose 80,000 feet (24 km; 15 mi) into the atmosphere and deposited ash in 11 U.S. states[5] and various Canadian provinces.[6] At the same time, snow, ice, and several entire glaciers on the volcano melted, forming a series of large lahars (volcanic mudslides) that reached as far as the Columbia River, nearly 50 miles (80 km) to the southwest. Less severe outbursts continued into the next day, only to be followed by other large, but not as destructive, eruptions later that year. The thermal energy released during the eruption was equal to 26 megatons of TNT.[7]
About 57 people were killed, including innkeeper and World War I veteran Harry R. Truman, photographers Reid Blackburn and Robert Landsburg, and volcanologist David A. Johnston.[8] Hundreds of square miles were reduced to wasteland, causing over $1 billion in damage (equivalent to $3.4 billion in 2023), thousands of animals were killed, and Mount St. Helens was left with a crater on its north side. At the time of the eruption, the summit of the volcano was owned by the Burlington Northern Railroad, but afterward, the railroad donated the land to the United States Forest Service.[9][10] The area was later preserved in the Mount St. Helens National Volcanic Monument and due to the eruption, the state recognized the month of May as "Volcano Awareness Month" and events are held at Mt. St. Helens, or within the region, to discuss the eruption, safety concerns, and to commemorate lives lost during the natural disaster.[11]
- ^ a b "St. Helens". Global Volcanism Program. Smithsonian Institution. Retrieved April 27, 2021.
- ^ Fisher, Heiken & Hulen 1998, p. 294.
- ^ "USGS M 5.7 Mt. St Helens earthquake trigger". earthquake.usgs.gov. Retrieved May 18, 2020.
- ^ "What was the largest landslide in the United States? In the world?". www.usgs.gov. Retrieved January 25, 2021.
- ^ Cite error: The named reference
WashPost2005was invoked but never defined (see the help page). - ^ Short, Dylan (March 19, 2019). "U of A researchers looking for Albertans who experienced volcano". edmontonjournal.com. Edmonton Journal. Retrieved May 1, 2019.
dust was found most heavily in the foothills area in southern Alberta, but may have drifted as far north as Red Deer.
- ^ "Mount Saint Helens Eruption - giph.io". giph.io. Archived from the original on September 26, 2017. Retrieved September 25, 2017.
- ^ "Those who lost their lives because of the May 18, 1980 eruption of Mount St. Helens" (PDF). KGW news. Archived from the original (PDF) on March 26, 2009.
- ^ Tilling, Robert I.; Topinka, Lyn; Swanson, Donald A. (1990). "Eruptions of Mount St. Helens: Past, Present, and Future". U.S. Geological Survey (Special Interest Publication). Archived from the original on October 26, 2011. Retrieved December 5, 2010. (adapted public domain text).
- ^ Runte, Alfred (1983). "Burlington Northern and the Legacy of Mount St. Helens". The Pacific Northwest Quarterly. 74 (3): 116–123. ISSN 0030-8803. JSTOR 40490550.
Burlington Northern, as co-owner of Mount St. Helens with the federal government, was especially concerned about the future of the peak, [...] Extending from the lip of the crater down the slopes opposite the blast area, arcing 90 degrees from due south to due west, lay the remainder of the square mile that originally had formed part of the [Northern Pacific Railroad's 1864] land grant. Clearly, this portion of the mountain had no commercial use but great value as the nucleus of the national park or monument already proposed by environmental groups. In recognition of the popularity of these proposals, Burlington Northern in 1982 restored the area to the federal government.
- ^ Barker, Cade (May 13, 2024). "Volcano Awareness Month: Numerous activities available in person, social media". The Reflector (Battle Ground, Washington). Retrieved May 21, 2024.
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