From: Myers and Theisen, 1994, Volcanic Event Notification at Mount St. Helens: IN: Casadevall, (ed.), 1994, Volcanic Ash and Aviation Safety: Proceedings of the First International Symposium on Volcanic Ash and Aviation Safety: USGS Bulletin 2047, 450p
When Mount St. Helens awoke in March 1980, there was an immediate need for the rapid dissemination of information about volcanic events and hazards. An emergency coordination center (ECC) was established at the U. S. Forest Service (USFS) facility in Vancouver, Washington. The facility was staffed 24 hours a day by USFS personnel experienced with emergency response. During critical times, the ECC was also staffed by representatives of the U. S. Geological Survey Cascades Volcano Observatory, emergency management agencies, and private companies. A communications network and telephone call-down procedures were developed to facilitate rapid dissemination of information about the activity of the volcano. Information was also disseminated through public meetings, press conferences, and briefings with governmental agencies and private businesses (Miller and others, 1981). Written "volcanic and seismic activity reports" were issued daily. These "daily updates" provided information on the status of the volcano and any significant changes or observations during the previous 24 hours.
Since 1980, this notification system has been modified in response to changes in volcanic activity, funding, and the concerns of government, business, and the public. Key changes include the capability of issuing written predictions weeks in advance of most eruptions; eliminating the need for 24-hour duty for both USFS/ECC and CVO staff except when eruptions are imminent; entering all predictions and updates into a computer "news" system for easy review by those on the call-down list; updating volcanic activity reports when the volcano is quiet; and, most recently, developing a seismic alarm to alert scientists to small events that occur without precursors.
Monitorings and Warnings
From: Wolfe and Pierson, 1995, Volcanic-Hazard Zonation for Mount St. Helens, Washington, 1995: USGS Open-File Report 95-497
Volcanic activity at Mount St. Helens is carefully monitored by the U. S. Geological Survey and the University of Washington. Some kinds of events, such as crater-wall avalanches or steam- driven explosions from the dome have occurred without warning in the past and may do so again. However, our experience since early 1980 at Mount St. Helens and elsewhere indicates that the monitoring is sufficient for us to detect the ascent of fresh magma that must take place before another large eruption. As in the past, interpretation of phenomena related to magma ascent will enable us to provide warnings and updated assessments of hazards.
Lahar and flood hazards are monitored by the U. S. Geological Survey and the National Weather Service; the latter agency has responsibility for providing warnings of floods, including lahars. Currently monitoring includes: (1) lake-level gages on Castle, Coldwater, and Spirit Lakes, (3) sensors to measure movement on the Castle Lake debris dam, (3) flow-vibration sensors in the North Fork Toutle River valley to detect passage of lahars or floods, and (4) streamflow gages in the North Fork, South Fork, and main channel of the Toutle River and in the Muddy River.
2007-04-11 08:38:55
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answer #1
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answered by BellaDonna 3
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The 1980 eruption of Mount St. Helens (VEI = 5, 1.2 km3 of material erupted) was a major catastrophic volcanic eruption in the 20th century. The eruption was the most significant to occur in the lower 48 U.S. states in recorded history, exceeding the destructive power and volume of material released by the 1915 eruption of California's Lassen Peak. The eruption was preceded by a two-month-long series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the mountain which created a huge bulge and a fracture system on Mount St. Helens' north slope. An earthquake at 8:32 a.m. on May 18, 1980, caused the entire weakened north face to slide away, suddenly exposing the partly molten, gas- and steam-rich rock in the volcano to lower pressure. The rock responded by exploding into a super-heated mix of pulverized lava and older rock that sped toward Spirit Lake so fast that it quickly passed the avalanching north face. A volcanic ash column rose high into the atmosphere and deposited ash in eleven U.S. states. At the same time, snow, ice, and several entire glaciers on the mountain melted, forming a series of large lahars (volcanic mudslides) that reached as far as the Columbia River. Less severe outbursts continued into the next day only to be followed by other large but not as destructive eruptions later in 1980. By the time the ash settled, 257 people (including innkeeper Harry Truman and geologist David A. Johnston) and thousands of animals were dead, hundreds of square miles (mi2) reduced to wasteland, over a billion U.S. dollars in damage had occurred, and the once-graceful face of Mount St. Helens was scarred with a huge crater opened on the north side of the mountain. The area was later preserved, as it was, in the Mount St. Helens National Volcanic Monument.
2016-04-01 09:21:30
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answer #2
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answered by Anonymous
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The Washington State Patrol was one of the main agencies helping out that day.
The Yakima Police (for the city of Yakima, WA)
Other local police for the individual towns that were affected, such as the Pullman, WA. police and the Washington State University campus police.
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2007-04-11 08:25:23
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answer #3
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answered by tlbs101 7
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