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California Integrated Seismic Network (CISN) Local Magnitude Determination in California and Vicinity

Uhrhammer, R. A. and Hellweg, M. and Hutton, K. and Lombard, P. and Walters, A. W. and Hauksson, E. and Oppenheimer, D. (2011) California Integrated Seismic Network (CISN) Local Magnitude Determination in California and Vicinity. Bulletin of the Seismological Society of America, 101 (6). pp. 2685-2693. ISSN 0037-1106. doi:10.1785/0120100106.

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Determining local magnitude (M_L) in a manner that is uniform and internally consistent for earthquakes throughout California and the vicinity is an important component of the California Integrated Seismic Network (CISN). We present a new local magnitude attenuation function and corresponding station adjustments that are valid throughout California. The new attenuation function is an analytic function of the radial hypocentral distance between 1 and 500 km. Associated station adjustments are also available for 1185 horizontal seismometer and accelerometer channels from five seismic networks operating in California. The new attenuation function and adjustments provide several advantages to CISN. They allow a more robust M_L computation, the M_Ls are more consistent between northern and southern California than they have been in the past, and because adjustments are now available for more station-network-channel-location codes (SNCLs), M_Ls can be computed for small earthquakes in more locations than was previously possible. In addition to describing our method for calibrating the new CISN M_L, we also present a tool for adding adjustments for new or upgraded stations.

Item Type:Article
Related URLs:
URLURL TypeDescription
Hauksson, E.0000-0002-6834-5051
Oppenheimer, D.0000-0002-6569-3640
Additional Information:© 2012 by the Seismological Society of America. Manuscript received 23 April 2010. We acknowledge the support of this study by the California Integrated Seismic Network (CISN;, the U.S. Geological Survey (USGS;, and the California Emergency Management Agency (CalEMA;
Group:Seismological Laboratory, Division of Geological and Planetary Sciences
Funding AgencyGrant Number
California Integrated Seismic Network (CISN)UNSPECIFIED
California Emergency Management Agency (CalEMA)UNSPECIFIED
Issue or Number:6
Record Number:CaltechAUTHORS:20120207-083401694
Persistent URL:
Official Citation:R. A. Uhrhammer, M. Hellweg, K. Hutton, P. Lombard, A. W. Walters, E. Hauksson, and D. Oppenheimer California Integrated Seismic Network (CISN) local magnitude determination in California and vicinity Bulletin of the Seismological Society of America (December 2011), 101(6):2685-2693
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:29162
Deposited By: Ruth Sustaita
Deposited On:07 Feb 2012 17:15
Last Modified:09 Nov 2021 17:04

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