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The distribution of modified Mercalli intensity in the 18 April 1906 San Francisco earthquake

John Boatwright and Howard Bundock
The distribution of modified Mercalli intensity in the 18 April 1906 San Francisco earthquake (in The 1906 San Francisco earthquake a century later, Brad T. Aagaard and Gregory C. Beroza)
Bulletin of the Seismological Society of America (April 2008) 98 (2): 890-900

Abstract

We analyze Boatwright and Bundock's (2005) modified Mercalli intensity (MMI) map for the 18 April 1906 San Francisco earthquake, reviewing their interpretation of the MMI scale and testing their correlation of 1906 cemetery damage with MMI intensity. We consider in detail four areas of the intensity map where Boatwright and Bundock (2005) added significantly to the intensity descriptions compiled by Lawson (1908). We show that the distribution of off-fault damage in Sonoma County suggests that the rupture velocity approached the P-wave velocity along Tomales Bay. In contrast, the falloff of intensity with distance from the fault appears approximately constant throughout Mendocino County. The intensity in Humboldt County appears somewhat higher than the intensity in Mendocino County, suggesting that the rupture process at the northern end of the rupture was relatively energetic and that there was directivity consistent with a subsonic rupture velocity on the section of the fault south of Shelter Cove. Finally, we show that the intensity sites added in Santa Cruz County change the intensity distribution so that it decreases gradually along the southeastern section of rupture from Corralitos to San Juan Bautista and implies that the stress release on this section of rupture was relatively low.


ISSN: 0037-1106
EISSN: 1943-3573
Serial Title: Bulletin of the Seismological Society of America
Serial Volume: 98
Serial Issue: 2
Title: The distribution of modified Mercalli intensity in the 18 April 1906 San Francisco earthquake
Title: The 1906 San Francisco earthquake a century later
Author(s): Boatwright, JohnBundock, Howard
Author(s): Aagaard, Brad T.
Author(s): Beroza, Gregory C.
Affiliation: U. S. Geological Survey, Menlo Park, CA, United States
Affiliation: U. S. Geological Survey, Menlo Park, CA, United States
Pages: 890-900
Published: 200804
Text Language: English
Publisher: Seismological Society of America, Berkeley, CA, United States
References: 26
Accession Number: 2008-084528
Categories: SeismologyEnvironmental geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables, geol. sketch maps
N39°00'00" - N41°00'00", W124°00'00" - W123°00'00"
Secondary Affiliation: Stanford University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 200825
Program Name: USGSOPNon-USGS publications with USGS authors
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