Constraining Lithospheric Structure across the Continental Borderland using Receiver Functions

Abstract

Due to its complex history of deformation, which includes subduction, rifting, and transtensional motions, the California Continental Borderland provides an interesting geological setting for studying how the structure of oceanic and continental plates responds to deformation. We calculate Ps and Sp receiver functions at permanent stations of the Southern California Seismic Network as well as ocean bottom seismometer data gathered as part of the ALBACORE seismic experiment in 2010-2011. Our results indicate that the Outer Borderland has been translated with little to no internal deformation, while the Inner Borderland underwent significant crustal thinning to compensate for the 90 degree clockwise rotation of the western Transverse Range block. We detect an oceanic seismic lithosphere-asthenosphere boundary at 58 km depth west of the Patton Escarpment. Sp common conversion point stacks confirm wholesale lithospheric thinning of the Inner Borderland and suggest the presence of a slab fragment beneath the Outer Borderland.