A California statewide three-dimensional seismic velocity model from both absolute and differential times
Bulletin of the Seismological Society of America
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Abstract
We obtain a seismic velocity model of the California crust and uppermost mantle using a regional-scale double-difference tomography algorithm. We begin by using absolute arrival-time picks to solve for a coarse three-dimensional (3D) P velocity (VP) model with a uniform 30 km horizontal node spacing, which we then use as the starting model for a finer-scale inversion using double-difference tomography applied to absolute and differential pick times. For computational reasons, we split the state into 5 subregions with a grid spacing of 10 to 20 km and assemble our final statewide VP model by stitching together these local models. We also solve for a statewide S-wave model using S picks from both the Southern California Seismic Network and USArray, assuming a starting model based on the VP results and a VP=VS ratio of 1.732. Our new model has improved areal coverage compared with previous models, extending 570 km in the SW-NE directionand 1320 km in the NW-SE direction. It also extends to greater depth due to the inclusion of substantial data at large epicentral distances. Our VP model generally agrees with previous separate regional models for northern and southern California, but we also observe some new features, such as high-velocity anomalies at shallow depths in the Klamath Mountains and Mount Shasta area, somewhat slow velocities in the northern Coast Ranges, and slow anomalies beneath the Sierra Nevada at midcrustal and greater depths. This model can be applied to a variety of regional-scale studies in California, such as developing a unified statewide earthquake location catalog and performing regional waveform modeling.
Suggested Citation
Lin, G., Thurber, C., Zhang, H., Hauksson, E., Shearer, P., Waldhauser, F., Brocher, T., Hardebeck, J., 2010, A California statewide three-dimensional seismic velocity model from both absolute and differential times: Bulletin of the Seismological Society of America, v. 100, no. 1, p. 225-240, https://doi.org/10.1785/0120090028.
ISSN: 1943-3573 (online)
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | A California statewide three-dimensional seismic velocity model from both absolute and differential times |
| Series title | Bulletin of the Seismological Society of America |
| DOI | 10.1785/0120090028 |
| Volume | 100 |
| Issue | 1 |
| Publication Date | January 27, 2010 |
| Year Published | 2010 |
| Language | English |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Bulletin of the Seismological Society of America |
| First page | 225 |
| Last page | 240 |