Three-Dimensional Basin and Fault Structure From a Detailed Seismic Velocity Model of Coachella Valley, Southern California

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dc.contributor.authorAjala, Rasheeden
dc.contributor.authorPersaud, Patriciaen
dc.contributor.authorStock, Joann M.en
dc.contributor.authorFuis, Gary S.en
dc.contributor.authorHole, John A.en
dc.contributor.authorGoldman, Marken
dc.contributor.authorScheirer, Danielen
dc.contributor.departmentGeosciencesen
dc.date.accessioned2020-06-25T17:03:56Zen
dc.date.available2020-06-25T17:03:56Zen
dc.date.issued2019-05en
dc.description.abstractThe Coachella Valley in the northern Salton Trough is known to produce destructive earthquakes, making it a high seismic hazard area. Knowledge of the seismic velocity structure and geometry of the sedimentary basins and fault zones is required to improve earthquake hazard estimates in this region. We simultaneously inverted first P wave travel times from the Southern California Seismic Network (39,998 local earthquakes) and explosions (251 land/sea shots) from the 2011 Salton Seismic Imaging Project to obtain a 3-D seismic velocity model. Earthquakes with focal depths <= 10 km were selected to focus on the upper crustal structure. Strong lateral velocity contrasts in the top similar to 3 km correlate well with the surface geology, including the low-velocity (<5 km/s) sedimentary basin and the high-velocity crystalline basement rocks outside the valley. Sediment thickness is similar to 4 km in the southeastern valley near the Salton Sea and decreases to <2 km at the northwestern end of the valley. Eastward thickening of sediments toward the San Andreas fault within the valley defines Coachella Valley basin asymmetry. In the Peninsular Ranges, zones of relatively high seismic velocities (similar to 6.4 km/s) between 2- and 4-km depth may be related to Late Cretaceous mylonite rocks or older inherited basement structures. Other high-velocity domains exist in the model down to 9-km depth and help define crustal heterogeneity. We identify a potential fault zone in Lost Horse Valley unassociated with mapped faults in Southern California from the combined interpretation of surface geology, seismicity, and lateral velocity changes in the model.en
dc.description.adminPublic domain – authored by a U.S. government employeeen
dc.description.notesWe thank three anonymous reviewers, the Editor in Chief, Uri ten Brink, and the Associate Editor, Kelly Liu, for their comments and suggestions, which significantly improved this manuscript. The SSIP was funded by the U.S. Geological Survey Multihazards Demonstration Project, and the National Science Foundation Earthscope and Margins Programs through grants OCE-0742253 (to California Institute of Technology) and OCE-0742263 (to Virginia Tech). This research was supported by Southern California Earthquake Center (SCEC) awards 15190 and 18074 and the U.S. Geological Survey grant G15AP00062. SCEC is funded by NSF Cooperative Agreement EAR-1033462 and USGS Cooperative Agreement G12AC20038. The SCEC contribution number for this paper is 8269. R. A. was also financially supported by the Society of Exploration Geophysicists Foundation through the merit-based scholarship program. We refer to the extensive acknowledgments in Rose et al. (2013) for permissions and assistance received for SSIP as a whole. The data have been archived at the IRIS DMC (ds.iris.edu/pic-ph5/metadata/SSIP/form.php). The 3-D velocity model as well as the derived basement and estimated Z2.5 surfaces important for seismic hazard assessment is available for download at our LSU research webpage (https://www.geol.lsu.edu/persaud/Data.html).All figures are plotted using the Generic Mapping Tools (Wessel et al., 2013).en
dc.description.sponsorshipU.S. Geological Survey Multihazards Demonstration Project; National Science Foundation Earthscope and Margins Programs [OCE-0742253, OCE-0742263]; Southern California Earthquake Center (SCEC) [15190, 18074]; U.S. Geological SurveyUnited States Geological Survey [G15AP00062]; NSFNational Science Foundation (NSF) [EAR-1033462]; USGSUnited States Geological Survey [G12AC20038]; Society of Exploration Geophysicists Foundation through the merit-based scholarship programen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1029/2018JB016260en
dc.identifier.eissn2169-9356en
dc.identifier.issn2169-9313en
dc.identifier.issue5en
dc.identifier.urihttp://hdl.handle.net/10919/99139en
dc.identifier.volume124en
dc.language.isoenen
dc.rightsCreative Commons CC0 1.0 Universal Public Domain Dedicationen
dc.rights.urihttp://creativecommons.org/publicdomain/zero/1.0/en
dc.subjectSan Andreas faulten
dc.subjectCoachella Valleyen
dc.subjectSalton Troughen
dc.subjectPeninsular Rangesen
dc.subjectEastern Transverse Rangesen
dc.subjectLost Horse Valleyen
dc.titleThree-Dimensional Basin and Fault Structure From a Detailed Seismic Velocity Model of Coachella Valley, Southern Californiaen
dc.title.serialJournal of Geophysical Research-Solid Earthen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen

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