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The Palos Verdes Terraces: Bathtub Rings from a Buried Thrust Fault

Steven N. Ward, & Gianluca Valensise

Published 1994, SCEC Contribution #43

Uplift of the Palos Verdes peninsula has long been associated with a northwest trending, southwest dipping, reverse fault. Unfortunately, the Palos Verdes Hills fault has no obvious surface displacement and little background seismicity to substantiate its dimension, orientation, or earthquake potential. In this paper we investigate the tectonic style and slip rate of the Palos Verdes Hills fault and the uplift history of the Palos Verdes Hills by analyzing the geometry of 13 marine terraces that encircle the peninsula in a bathtub ring configuration. Elevations of 211 terrace remnants constrain a fault model with 3.0 to 3.7 mm yr−1 of oblique, dextral/reverse slip on a fault dipping 67° at 6 to 12 km depth beneath the peninsula. If the rate was constant through time, fault inception would have occurred 2.4–3.0 Ma. We propose that the largest credible earthquakes on the fault have magnitude ≈6¾ and could revisit every 2000 years.

Ward, S. N., & Valensise, G. (1994). The Palos Verdes Terraces: Bathtub Rings from a Buried Thrust Fault. Journal of Geophysical Research, 99(3), 4485-4494.