High-resolution seismic imaging of the plate boundary in northern Baja California and southern California using double-pair double-difference tomography

• Published in: Earth and planetary science letters 2021-08, Vol.568, p.117004, Article 117004
• Main Authors: Share, P.-E., Castro, R.R., Vidal-Villegas, J.A., Mendoza, L., Ben-Zion, Y.
• Format: Article
• Language: English
• Subjects: double-difference tomography; Peninsular Ranges; Salton Trough; seismic velocities; tectonic and fault structure
• ISSN: 0012-821X; 1385-013X
• DOI: 10.1016/j.epsl.2021.117004

•Double-difference tomography of plate boundary through Salton Trough.•∼4,500,000 data points analyzed from >21,000 earthquakes and ∼200 stations.•Salton Trough highly variable in crustal structure, damage, fluids and temperature.•Anomalous velocity corridor northwestward from 2010 El-Mayor Cucapah rupture.•Weak fluid-rich corridor represents a key branch of the active plate boundary. We image seismic properties of the plate boundary through northern Baja California and southernmost California using a double-difference tomography and earthquake relocation algorithm that incorporates both event-pair and station-pair data. The data are derived from seismic networks in southern California (SCSN) and northern Baja California (CICESE). It comprises >700,000 travel times (P and S) associated with ∼200 seismic stations and >21,000 local earthquakes from 2003-2018, along with >2,000,000 event-pair and >1,500,000 station-pair double-differences derived from these travel times. In the upper crust, low VP values in the resultant models imply deep sediments and sedimentary rocks northwest of the Salton Sea and around the northern end of the Imperial fault. Low VS values indicate regions of rock damage at the northern ends of the Sierra Juarez fault zone and Laguna Salada fault, and the southern end of the San Jacinto fault zone (SJFZ). Shallow seismicity (d