Insights into the geometry and evolution of the southern San Andreas fault from geophysical data, southern California

Abstract Two new joint gravity-magnetic models in northern Coachella Valley provide additional evidence for a steep northeast dip of the Mission Creek strand southern San Andreas fault (southern California, USA). Gravity modeling indicates Banning upper 1–2 km Valley. The and its continuation to southeast (Coachella segment) coincide with northeastern margin Cenozoic basin are marked by prominent gravity magnetic gradients that consistent these strands having accommodated >160 right-lateral 1–5 vertical displacement. These anomalies best fit moderate dip. Such geometry is further supported seismicity, reflectivity, geodesy, boundary-element modeling. We explore possibility forming were originally near have rotated into their present orientation underplating localized high-velocity, lower-crustal prong within Peninsular Ranges batholith. Reconstructions offset suggest this crystalline body was translated Gorgonio Pass area at time major reorganization 1.1–1.3 Ma.