The Palos Verdes Fault offshore southern California: late Pleistocene to present tectonic geomorphology, seascape evolution and slip rate estimate based on AUV and ROV surveys

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. To characterize the near-seafloor fault morphology, tectonic influences on continental slope sedimentary processes and late Pleistocene to present slip rate, a grid of high-resolution multibeam bathymetric data, and chirp subbottom profiles were acquired with an autonomous underwater vehicle (AUV) along the main trace of PVF in water depths between 250 and 600 m. Radiocarbon dates were obtained from vibracores collected using a remotely operated vehicle (ROV) and ship-based gravity cores. The PVF is expressed as a well-defined seafloor lineation marked by subtle along-strike bends. Right-stepping transtensional bends exert first-order control on sediment flow dynamics and the spatial distribution of Holocene depocenters; deformed strata within a small pull-apart basin record punctuated growth faulting associated with at least three Holocene surface ruptures. An upper (shallower) landslide scarp, a buried sedimentary mound, and a deeper scarp have been right-laterally offset across the PVF by 55 ± 5, 52 ± 4 , and 39 ± 8 m, respectively. The ages of the upper scarp and buried mound are approximately 31 ka; the age of the deeper scarp is bracketed to 17–24 ka. These three piercing points bracket the late Pleistocene to present slip rate to 1.3–2.8 mm/yr and provide a best estimate of 1.6–1.9 mm/yr. The deformation observed along the PVF is characteristic of strike-slip faulting and accounts for 20–30% of the total right-lateral slip budget accommodated offshore Southern California.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The Palos Verdes Fault offshore southern California: late Pleistocene to present tectonic geomorphology, seascape evolution and slip rate estimate based on AUV and ROV surveys
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1002/2015JB011938
Volume 120
Issue 7
Year Published 2015
Language English
Publisher American Geophysical Union
Contributing office(s) Pacific Coastal and Marine Science Center
Description 25 p.
First page 4734
Last page 4758
Country United States
State California
Other Geospatial Palos Verdes Fault
Online Only (Y/N) N
Additional Online Files (Y/N) N