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Probabilistic assessment of precipitation-triggered landslides using historical records of landslide occurence, Seattle, Washington

Environmental and Engineering Geoscience

By:
, , , , , and
DOI: 10.2113/10.2.103

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Abstract

Ninety years of historical landslide records were used as input to the Poisson and binomial probability models. Results from these models show that, for precipitation-triggered landslides, approximately 9 percent of the area of Seattle has annual exceedance probabilities of 1 percent or greater. Application of the Poisson model for estimating the future occurrence of individual landslides results in a worst-case scenario map, with a maximum annual exceedance probability of 25 percent on a hillslope near Duwamish Head in West Seattle. Application of the binomial model for estimating the future occurrence of a year with one or more landslides results in a map with a maximum annual exceedance probability of 17 percent (also near Duwamish Head). Slope and geology both play a role in localizing the occurrence of landslides in Seattle. A positive correlation exists between slope and mean exceedance probability, with probability tending to increase as slope increases. Sixty-four percent of all historical landslide locations are within 150 m (500 ft, horizontal distance) of the Esperance Sand/Lawton Clay contact, but within this zone, no positive or negative correlation exists between exceedance probability and distance to the contact.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Probabilistic assessment of precipitation-triggered landslides using historical records of landslide occurence, Seattle, Washington
Series title:
Environmental and Engineering Geoscience
DOI:
10.2113/10.2.103
Volume
10
Issue:
2
Year Published:
2004
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Environmental and Engineering Geoscience
First page:
103
Last page:
122
Number of Pages:
20