Puente Hills blind-thrust system, Los Angeles, California

Bulletin of the Seismological Society of America
By: , and 

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Abstract

We describe the three-dimensional geometry and Quaternary slip history of the Puente Hills blind-thrust system (PHT) using seismic reflection profiles, petroleum well data, and precisely located seismicity. The PHT generated the 1987 Whittier Narrows (moment magnitude [Mw] 6.0) earthquake and extends for more than 40 km along strike beneath the northern Los Angeles basin. The PHT comprises three, north-dipping ramp segments that are overlain by contractional fault-related folds. Based on an analysis of these folds, we produce Quaternary slip profiles along each ramp segment. The fault geometry and slip patterns indicate that segments of the PHT are related by soft-linkage boundaries, where the fault ramps are en echelon and displacements are gradually transferred from one segment to the next. Average Quaternary slip rates on the ramp segments range from 0.44 to 1.7 mm/yr, with preferred rates between 0.62 and 1.28 mm/yr. Using empirical relations among rupture area, magnitude, and coseismic displacement, we estimate the magnitude and frequency of single (Mw 6.5-6.6) and multisegment (Mw 7.1) rupture scenarios for the PHT.

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Publication type Article
Publication Subtype Journal Article
Title Puente Hills blind-thrust system, Los Angeles, California
Series title Bulletin of the Seismological Society of America
DOI 10.1785/0120010291
Volume 92
Issue 8
Year Published 2002
Language English
Publisher Seismological Society of America
Contributing office(s) Geologic Hazards Science Center
Description 15 p.
First page 2946
Last page 2960
Country United States
State California
County Los Angeles
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