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Maps Showing Seismic Landslide Hazards in Anchorage, Alaska

Scientific Investigations Map 3077

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Abstract

The devastating landslides that accompanied the great 1964 Alaska earthquake showed that seismically triggered landslides are one of the greatest geologic hazards in Anchorage. Maps quantifying seismic landslide hazards are therefore important for planning, zoning, and emergency-response preparation. The accompanying maps portray seismic landslide hazards for the following conditions: (1) deep, translational landslides, which occur only during great subduction-zone earthquakes that have return periods of =~300-900 yr; (2) shallow landslides for a peak ground acceleration (PGA) of 0.69 g, which has a return period of 2,475 yr, or a 2 percent probability of exceedance in 50 yr; and (3) shallow landslides for a PGA of 0.43 g, which has a return period of 475 yr, or a 10 percent probability of exceedance in 50 yr. Deep, translational landslide hazard zones were delineated based on previous studies of such landslides, with some modifications based on field observations of locations of deep landslides. Shallow-landslide hazards were delineated using a Newmark-type displacement analysis for the two probabilistic ground motions modeled.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Maps Showing Seismic Landslide Hazards in Anchorage, Alaska
Series title:
Scientific Investigations Map
Series number:
3077
ISBN:
9781411324244
Edition:
Version 1.0
Year Published:
2009
Language:
ENGLISH
Publisher:
U.S. Geological Survey
Contributing office(s):
Geologic Hazards Team
Description:
Report: iv, 11 p.; 2 Plates: each sheet 36 x 48 inches; Downloads Directory
Projection:
Universal Transverse Mercator
Scale:
25000
Online Only (Y/N):
N
Additional Online Files(Y/N):
Y