Latest Pleistocene and Holocene slip rate for the San Bernardino strand of the San Andreas fault, Plunge Creek, Southern California: Implications for strain partitioning within the southern San Andreas fault system for the last ∼35 k.y.

Sally F. McGill, Katherine J. Kendrick, Lewis A. Owen, & Ray J. Weldon

Published January 2, 2013, SCEC Contribution #1233

Radiocarbon and optically stimulated luminescence dating of an offset channel margin of Plunge Creek of latest Pleistocene age, indicates a slip rate of 13 +/- 9 mm/yr for the San Bernardino strand of the San Andreas fault. This is significantly less than the published 25 mm/yr rate measured to the northwest in Cajon Pass, which has often been extrapolated southeastward along the San Bernardino section of the fault. Our results suggest instead that a substantial portion of that 25 mm/yr rate at Cajon Pass transfers southeastward to the San Jacinto fault. Results from two other sites (not presented here) located between Cajon Pass and Plunge Creek support this interpretation. The latest Pleistocene slip rate at Plunge Creek is still substantially higher than rates inferred for the San Bernardino section of the San Andreas fault from elastic block modeling of geodetic data.

Citation
McGill, S. F., Kendrick, K. J., Owen, L. A., & Weldon, R. J. (2013). Latest Pleistocene and Holocene slip rate for the San Bernardino strand of the San Andreas fault, Plunge Creek, Southern California: Implications for strain partitioning within the southern San Andreas fault system for the last ∼35 k.y.. Geological Society of America Bulletin, 125(1-2), 48-72. doi: 10.1130/B30647.1.