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Spectral Discrimination between Quarry Blasts and Earthquakes in Southern California

Allmann, Bettina P. and Shearer, Peter M. and Hauksson, Egill (2008) Spectral Discrimination between Quarry Blasts and Earthquakes in Southern California. Bulletin of the Seismological Society of America, 98 (4). pp. 2073-2079. ISSN 0037-1106. doi:10.1785/0120070215.

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We compare P-wave spectra of quarry blasts and earthquakes recorded by the southern California seismic network (SCSN) between 2000 and 2005, with the goal of developing methods to discriminate between these events. We process the spectra using an iterative robust least-squares method to isolate source, receiver, and propagation path contributions. This corrects for first-order attenuation structure, as well as near-receiver site effects and any errors in the instrument response functions. Using the earthquake spectra and a simple {omega}^-2 source model, we compute an empirical Green’s function (EGF) to remove the trade-off between the source terms and other parameters in our model. A constant stress-drop model gives a good fit to the observed average earthquake spectra over a wide range of moment magnitude, but provides a mediocre fit to the average quarry blast spectra, which have a generally steeper fall-off at high frequencies than {omega}^-2. We also compare P- and S-wave amplitudes and find modestly smaller average S amplitudes for the explosions compared to the earthquakes. For southern California, the root-mean-square (rms) misfit of P-wave spectra to an {omega}^-2 source model is a more reliable explosion discriminant than the S-to-P amplitude ratio and works for about 90% of the events.

Item Type:Article
Related URLs:
URLURL TypeDescription
Shearer, Peter M.0000-0002-2992-7630
Hauksson, Egill0000-0002-6834-5051
Additional Information:© 2008 Seismological Society of America. Manuscript received 24 August 2007. We thank Guoqing Lin for relocating all of the events. This research was supported by the Air Force Research Laboratory, Contract Number FA8718-06-C-0004, and by the Southern California Earthquake Center. SCEC is funded by the National Science Foundation (NSF) Cooperative Agreement Number EAR-0106924 and the U.S. Geological Survey (USGS) Cooperative Agreement Number 02HQAG0008. The SCEC contribution number for this article is 1145.
Group:Seismological Laboratory
Funding AgencyGrant Number
Air Force Research LaboratoryFA8718-06-C-0004
Southern California Earthquake Center (SCEC)UNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Southern California Earthquake Center (SCEC)1145
Issue or Number:4
Record Number:CaltechAUTHORS:ALLbssa08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11593
Deposited By: Archive Administrator
Deposited On:09 Sep 2008 03:56
Last Modified:08 Nov 2021 22:00

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