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U.S. Geological Survey Fact Sheet 001-01
Online version 1.0

Earthquake Shaking—Finding the "Hot Spots"


Ned Field, Lucile Jones, Tom Jordan, Mark Benthien, and Lisa Wald

A new Southern California Earthquake Center study has quantified how local geologic conditions affect the shaking experienced in an earthquake. The important geologic factors at a site are (1) softness of the rock or soil near the surface and (2) thickness of the sediments above hard bedrock. Even when these "site effects" are taken into account, however, each earthquake exhibits unique "hotspots" of anomalously strong shaking. Better predictions of strong ground shaking will therefore require additional geologic data and more comprehensive computer simulations of individual earthquakes.

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Find out how site effects are related to earthquake shaking in southern California from USGS Open-File Report 01-164

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For questions about the content of this report, contact Ned Field

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Maintained by: Michael Diggles
Created: January 16, 2001
Last modified: February 23, 2005 (mfd)