Fault zone characteristics and basin complexity in the southern Salton Trough, California
Abstract
Ongoing oblique slip at the Pacific–North America plate boundary in the Salton Trough produced the Imperial Valley (California, USA), a seismically active area with deformation distributed across a complex network of exposed and buried faults. To better understand the shallow crustal structure in this region and the connectivity of faults and seismicity lineaments, we used data primarily from the Salton Seismic Imaging Project to construct a three-dimensional P-wave velocity model down to 8 km depth and a velocity profile to 15 km depth, both at 1 km grid spacing. A V_P = 5.65–5.85 km/s layer of possibly metamorphosed sediments within, and crystalline basement outside, the valley is locally as thick as 5 km, but is thickest and deepest in fault zones and near seismicity lineaments, suggesting a causative relationship between the low velocities and faulting. Both seismicity lineaments and surface faults control the structural architecture of the western part of the larger wedge-shaped basin, where two deep subbasins are located. We estimate basement depths, and show that high velocities at shallow depths and possible basement highs characterize the geothermal areas.
Additional Information
© 2016 Geological Society of America. Received 26 April 2016. Revision received 1 July 2016. Accepted 4 July 2016. We thank P. Umhoefer, G. Axen, D. Scheirer, V. Langenheim, editor Bob Holdsworth, and an anonymous reviewer for their comments on the manuscript. The Salton Seismic Imaging Project (SSIP) was funded by the U.S. Geological Survey Multihazards Project, and the National Science Foundation Earthscope and Margins Programs through grants OCE-0742253 (to California Institute of Technology) and OCE-0742263 (to Virginia Polytechnic Institute and State University). Persaud was supported by U.S. Geological Survey grant G15AP00062.Additional details
- Eprint ID
- 69217
- Resolver ID
- CaltechAUTHORS:20160726-090423974
- NSF
- OCE-0742253
- NSF
- OCE-0742263
- USGS
- G15AP00062
- Created
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2016-07-26Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory, Division of Geological and Planetary Sciences