Cordilleran Section - 116th Annual Meeting - 2020

Paper No. 17-9
Presentation Time: 10:55 AM

STRAIN PARTITIONING CAN EXPLAIN DISPARATE CROSS-FAULT CORRELATIONS ALONG THE SAN ANDREAS FAULT, SOUTHERN CALIFORNIA, U.S.A


COFFEY, Kevin T., Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095-1567; Earth Sciences, El Camino College, Torrance, CA 90506

When strain partitioning is taken into account, disparate cross-fault correlations along the southern San Andreas fault become compatible. Comparison of these correlations has resulted in decades of debate, predicated on the assumption that cumulative slip on the Mojave segment of the San Andreas fault should be the same as that on adjacent segments. However, along the anomalously oriented Mojave segment of the San Andreas fault, dextral slip experienced by adjacent segments is accommodated by a combination of dextral slip on the fault itself, and a zone of north-south shortening beside it. Therefore, it is the vector sum of the dextral slip along this segment and the magnitude of north-south shortening beside it that should equal the dextral slip on adjacent segments of the San Andreas fault. This relationship allows reconciliation of the approximately 215 km of cumulative dextral slip implied for the San Andreas fault system (including slip on the San Jacinto fault, but less slip transferred off the San Andreas fault in the eastern Transverse Ranges) south of the Mojave segment with the approximately 160 km of cumulative dextral slip implied along the Mojave segment.