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Debris flow, debris avalanche and flood hazards at and downstream from Mount Rainier, Washington

Hydrologic Atlas 729

By:
and

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Abstract

Mount Rainier volcano has produced many large debris flows and debris avalanches during the last 10,000 years. These flows have periodically traveled more than 100 kilometers from the volcano to inundate parts of the now-populated Puget Sound Lowland. Meteorological floods also have caused damage, but future effects will be partly mitigated by reservoirs. Mount Rainier presents the most severe flow risks of any volcano in the United States. Volcanic debris flows (lahars) are of two types: (1) cohesive, relatively high clay flows originating as debris avalanches, and (2) noncohesive flows with less clay that begin most commonly as meltwater surges. Three case histories represent important subpopulations of flows with known magnitudes and frequencies. The risks of each subpopulation may be considered for general planning and design. A regional map illustrates the extent of inundation by the case-history flows, the largest of which originated as debris avalanches and moved from Mount Rainier to Puget Sound. The paleohydrologic record of these past flows indicates the potential for inundation by future flows from the volcano. A map of the volcano and its immediate vicinity shows examples of smaller debris avalanches and debris flows in the 20th century.

Study Area

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Debris flow, debris avalanche and flood hazards at and downstream from Mount Rainier, Washington
Series title:
Hydrologic Atlas
Series number:
729
Edition:
-
Year Published:
1995
Language:
ENGLISH
Description:
2 maps ;57 x 52 cm., and 114 x 99 cm., on sheets 129 x 106 cm. and 71 x 61 cm., folded in envelope 30 x 24 cm. +1 pamphlet (9 p. ; 28 cm.)
Scale:
50000
Online Only (Y/N):
N
Additional Online Files (Y/N):
N