HIGH RESOLUTION FAULT KINEMATICS OF THE SAN PEDRO BASIN FAULT, CALIFORNIA CONTINENTAL BORDERLAND

The California Continental Borderland is an unusual coastal zone that is undergoing transition from a convergent continental margin to an oblique transform margin, dominated by the San Andreas and similar faults. Major Borderland features are NNW-SSE trending seafloor basins and ridges, many bounded by strike-slip faults. The San Pedro Basin fault is located between the Palos Verdes peninsula and Catalina Island. Seismic reflection provides high resolution images of the upper part of the fault, showing the seafloor expression. In addition, there are significant differences on either side of the fault. There are onlaps on both sides, but on the SW side (toward Catalina), the onlapping sediments are lower in the section than on the NE side. This corresponds to an earlier time when Catalina may have been uplifting more than Palos Verdes, but the opposite is true at the present time which may represent a change in the motion along the fault. The microseismicity of the San Pedro Basin is characterized by a low-level activity rate, magnitudes smaller than three, spatially scattered events with minor clustering, and localized alignment, but offset, with the San Pedro Basin fault. We are relocating the events and correlating with the seismic reflection interpretations of the fault location and orientation.