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The Mount Rainier Volcano Lahar Warning System is a loose-knit, emergency notification and warning system developed by the United States Geological Survey in 1998, and now operated by the Pierce County Department of Emergency Management and several cities . It is supposed to assist in the evacuation of the Puyallup River Valley in Washington state in the event of a volcanic eruption of Mount Rainier. ==History== Mount Rainier, an active volcano in Washington state which last erupted in 1882, has occasionally buried sections of the Puyallup River valley in volcanic mudflow. Currently, more than 150,000 people live on the deposits of Mount Rainier lahars that have occurred within the last 6,000 years.〔http://www.co.pierce.wa.us/pc/Abtus/ourorg/dem/EMDiv/VHRP/I.htm〕 Geologists consider Mount Rainier the most dangerous mountain in the United States, 〔Rainier: Danger at our door (), ''Seattle Times'', May 16, 2000, Accessed March 8, 2009.〕 and the Geological Survey has estimated there is a 1-in-7 chance of a catastrophic lahar at Mount Rainier occurring in the next 75 years. 〔5 Natural Disasters Headed for the United States (), ''Popular Mechanics'', October 2006, Accessed March 8, 2009.〕 The Pacific Northwest Seismic Network (PNSN), operated by the University of Washington, provides continuous monitoring of seismic activity in the area and is intended to provide first indication of volcanic unrest at Mount Rainier. However, while the PNSN is able to detect that a lahar-generating event has occurred, it is not able to determine the location or flow of debris. Beginning in 1998 a lahar-detection system consisting of five acoustic flow monitors was installed around Mount Rainier which would help identify the speed and direction of a lahar. Comprehensive coverage, which would require 30 to 40 such monitors, has yet to be installed.〔http://www.co.pierce.wa.us/pc/Abtus/ourorg/dem/EMDiv/VHRP/V.htm〕 Since 2000, the nascent lahar detection system has been operated by the Pierce County Department of Emergency Management which also has responsibility for coordination of public information and evacuation of areas of potential impact. Tacoma, at the mouth of the Puyallup, is only 37 miles (60 km) west of Mount Rainier, and moderately sized towns such as Puyallup and Orting are only 27 and 20 miles (43 and 32 km) away, respectively. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mount Rainier Volcano Lahar Warning System」の詳細全文を読む スポンサード リンク
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