U.S. Geological Survey Open-File Report 98-428
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Introduction Mount Rainier at 4393
meters (14,410 feet) is the highest peak in the Cascade Range; a dormant
volcano having glacier ice that exceeds that of any other mountain in the
conterminous United States. This tremendous mass of rock and ice, in
combination with great topographic relief, poses a variety of geologic
hazards, both during inevitable future eruptions and during the intervening
periods of repose. The volcano's past behavior is the best guide to possible
future hazards. The written history (about A.D. 1820) of Mount Rainier
includes one or two small eruptions, several small debris avalanches, and
many small lahars (debris flows originating on a volcano). In addition,
prehistoric deposits record the types, magnitudes, and frequencies of other
events, and areas that were affected. Mount Rainier deposits produced since
the latest ice age (approximately during the past 10,000 years) are well
preserved. Studies of these deposits indicate we should anticipate potential
hazards in the future. Some phenomena only occur during eruptions such as
tephra falls, pyroclastic flows and surges, ballistic projectiles, and lava
flows while others may occur without eruptive activity such as debris
avalanches, lahars, and floods. Five geographic information system (GIS) volcano hazard data layers used to produce the Mount Rainier volcano hazard map in OFR 98-428 (Hoblitt and others, 1998) are included in this data set. Case 1, case 2, and case 3 layers were delineated by scientists at the Cascade Volcano Observatory and depict various lahar innundation zones around the mountain. Two additional layers delineate areas that may be affected by post-lahar sedimentation (postlahar layer) and pyroclastic flows (pyroclastic layer). |
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2007
U.S. Department of the Interior
U.S. Geological Survey
intro.html
March, 2007