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Southern California Hypocenter Relocation with Waveform Cross-Correlation, Part 1: Results Using the Double-Difference Method

Hauksson, Egill and Shearer, Peter (2005) Southern California Hypocenter Relocation with Waveform Cross-Correlation, Part 1: Results Using the Double-Difference Method. Bulletin of the Seismological Society of America, 95 (3). pp. 896-903. ISSN 0037-1106. https://resolver.caltech.edu/CaltechAUTHORS:20130227-105011558

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Abstract

We present the results of relocating 327,000 southern California earthquakes that occurred between 1984 and 2002. We apply time-domain waveform cross-correlation for P and S waves between each event and 100 neighboring events identified from the catalog based on a 3D velocity model. To simplify the computation, we first divide southern California into five polygons, such that there are ∼100,000 events or less in each region. The polygon boundaries are chosen to lie in regions of sparse seismicity. We calculate and save differential times from the peaks in the cross-correlation functions and use a spline interpolation method to achieve a nominal timing precision of 0.001 sec. These differential times, together with existing P- and S-phase picks, are input to the double-difference program of Waldhauser and Ellsworth (2000, 2002) to calculate refined hypocenters. We divide the southern California region into grid cells and successively relocate hypocenters within each grid cell. The overall resulting pattern of seismicity is more focused than the previously determined pattern from 1D or 3D models. The new improved locations are more clustered, in many cases by a factor of two or three, and often show clear linear alignments. In particular, the depth distribution is improved and less affected by layer boundaries in velocity models or other similar artifacts.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1785/0120040167DOIArticle
http://bssa.geoscienceworld.org/content/95/3/896PublisherArticle
ORCID:
AuthorORCID
Hauksson, Egill0000-0002-6834-5051
Shearer, Peter0000-0002-2992-7630
Additional Information:© 2005 Bulletin of the Seismological Society of America. Manuscript received 23 August 2004. The Southern California Seismic Network (SCSN), Kate Hutton and her staff, produced the earthquake phase picks used in this study, and the data were made available at the Southern California Earthquake Data Center. We thank Andy Michael of U.S. Geological Survey, Menlo Park, for making available his technique for relocating the catalog with the grid-cell method. We thank L. Jones, J. Hardebeck, and D. Schaff for reviewing the manuscript, and I. Wong for constructive editorial comments. The figures were done using GMT (Wessel and Smith, 1991). This work was supported by NEHRP/USGS Grant 04HQGR0052 and by SCEC, which is funded by NSF Cooperative Agreement EAR-0106924 and USGS Cooperative Agreement 02HQAG0008; SCEC contribution no. 820. Contribution no. 9105, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
USGS04HQGR0052
Southern California Earthquake Center (SCEC)UNSPECIFIED
NSFEAR-0106924
USGS02HQAG0008
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Southern California Earthquake Center (SCEC)820
Caltech Division of Geological and Planetary Sciences9105
Issue or Number:3
Record Number:CaltechAUTHORS:20130227-105011558
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130227-105011558
Official Citation:Egill Hauksson and Peter Shearer Southern California Hypocenter Relocation with Waveform Cross-Correlation, Part 1: Results Using the Double-Difference Method Bulletin of the Seismological Society of America, June 2005, v. 95, p. 896-903, doi:10.1785/0120040167
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37174
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:28 Feb 2013 15:25
Last Modified:03 Oct 2019 04:45

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