Three-Dimensional Seismic Velocity Structure and Precise Earthquake Relocations in the Salton Trough, Southern California

Abstract

Research Article| October 01, 2013 Three‐Dimensional Seismic Velocity Structure and Precise Earthquake Relocations in the Salton Trough, Southern California Guoqing Lin Guoqing Lin Division of Marine Geology and Geophysics, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149 Search for other works by this author on: GSW Google Scholar Author and Article Information Guoqing Lin Division of Marine Geology and Geophysics, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149 Publisher: Seismological Society of America First Online: 14 Jul 2017 Online ISSN: 1943-3573 Print ISSN: 0037-1106 Bulletin of the Seismological Society of America (2013) 103 (5): 2694–2708. https://doi.org/10.1785/0120120286 Article history First Online: 14 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Guoqing Lin; Three‐Dimensional Seismic Velocity Structure and Precise Earthquake Relocations in the Salton Trough, Southern California. Bulletin of the Seismological Society of America 2013;; 103 (5): 2694–2708. doi: https://doi.org/10.1785/0120120286 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract I present a new 3D seismic velocity model and high‐precision earthquake relocations between 1981 and 2010 near the Salton Trough and the San Jacinto fault zone. The simul2000 tomography algorithm is applied to derive the 3D VP and VP/VS models using first arrivals of a composite event data set. The final VP model correlates with geological features at shallow depths and is more consistent with the refraction studies than the starting 3D regional‐scale model. The VP/VS model shows strong variations in the upper crust and is dominated by relatively low values (below 1.7) in the middle crust except for the Salton Trough and the Imperial Valley. The newly resolved model is used to relocate all the seismicity in the study area. I then apply the similar‐event cluster analysis and differential‐time relocation approach based on waveform cross‐correlation data to the 3D relocated events. A dramatic sharpening of seismicity patterns is obtained after using these methods. The new locations are more tightly clustered than the previous catalogs mainly due to the different absolute locations. The depth distribution along a basal surface may suggest the existence of a detachment fault from the north end of the Salton Trough to United States–Mexico border. The fine‐scale velocity structure and precise earthquake relocations will be helpful for investigating the fault geometry, seismicity, stress interaction, and other seismological studies for southern California.Online Material: Figures of model resolution tests, cross‐sectional comparisons of different P‐velocity models, and earthquake depth distributions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.