Please use this identifier to cite or link to this item:
|Title:||Structure and seismic hazard of the ventura avenue anticline and ventura fault, California : prospect for large, multisegment ruptures in the western transverse ranges||Authors:||Hubbard, Judith
Shaw, John H.
Pratt, Thomas L.
Rockwell, Thomas K.
|Keywords:||DRNTU::Science::Geology::Volcanoes and earthquakes||Issue Date:||2014||Source:||Hubbard, J., Shaw, J. H., Dolan, J., Pratt, T. L., McAuliffe, L., & Rockwell, T. K. (2014). Structure and Seismic Hazard of the Ventura Avenue Anticline and Ventura Fault, California: Prospect for Large, Multisegment Ruptures in the Western Transverse Ranges. Bulletin of the Seismological Society of America, 104(3), 1070-1087.||Series/Report no.:||Bulletin of the seismological society of America||Abstract:||The Ventura Avenue anticline is one of the fastest uplifting structures in southern California, rising at ∼5 mm/yr. We use well data and seismic reflection profiles to show that the anticline is underlain by the Ventura fault, which extends to seismogenic depth. Fault offset increases with depth, implying that the Ventura Avenue anticline is a fault‐propagation fold. A decrease in the uplift rate since ∼30±10 ka is consistent with the Ventura fault breaking through to the surface at that time and implies that the fault has a recent dip‐slip rate of ∼4.4–6.9 mm/yr. To the west, the Ventura fault and fold trend continues offshore as the Pitas Point fault and its associated hanging wall anticline. The Ventura–Pitas Point fault appears to flatten at about 7.5 km depth to a detachment, called the Sisar decollement, then step down on a blind thrust fault to the north. Other regional faults, including the San Cayetano and Red Mountain faults, link with this system at depth. We suggest that below 7.5 km, these faults may form a nearly continuous surface, posing the threat of large, multisegment earthquakes. Holocene marine terraces on the Ventura Avenue anticline suggest that it grows in discrete events with 5–10 m of uplift, with the latest event having occurred ∼800 years ago (Rockwell, 2011). Uplift this large would require large earthquakes (Mw 7.7–8.1) involving the entire Ventura/Pitas Point system and possibly more structures along strike, such as the San Cayetano fault. Because of the local geography and geology, such events would be associated with significant ground shaking amplification and regional tsunamis.||URI:||https://hdl.handle.net/10356/104839
|ISSN:||0037-1106||DOI:||10.1785/0120130125||Rights:||© 2014 Seismological Society of America. This paper was published in Bulletin of the Seismological Society of America and is made available as an electronic reprint (preprint) with permission of Seismological Society of America. The paper can be found at the following official DOI: [http://dx.doi.org/ 10.1785/0120130125]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.||Fulltext Permission:||open||Fulltext Availability:||With Fulltext|
|Appears in Collections:||EOS Journal Articles|
Files in This Item:
|Structure and seismic hazard of the Ventura Avenue anticline and ventura fault, California Prospect for large, multisegment ruptures in the western transverse ranges.pdf||3.43 MB||Adobe PDF|
Updated on Dec 28, 2021
Updated on Mar 6, 2021
Page view(s) 10655
Updated on Jun 29, 2022
Updated on Jun 29, 2022
Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.