Source complexity of the 1987 Whittier Narrows, California, earthquake from the inversion of strong motion records

Journal of Geophysical Research Solid Earth
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Abstract

Strong motion records for the Whittier Narrows earthquake are inverted to obtain the history of slip. Both constant rupture velocity models and variable rupture velocity models are considered. The results show a complex rupture process within a relatively small source volume, with at least four separate concentrations of slip. Two sources are associated with the hypocenter, the larger having a slip of 55–90 cm, depending on the rupture model. These sources have a radius of approximately 2–3 km and are ringed by a region of reduced slip. The aftershocks fall within this low slip annulus. Other sources with slips from 40 to 70 cm each ring the central source region and the aftershock pattern. All the sources are predominantly thrust, although some minor right-lateral strike-slip motion is seen. The overall dimensions of the Whittier earthquake from the strong motion inversions is 10 km long (along the strike) and 6 km wide (down the dip). The preferred dip is 30° and the preferred average rupture velocity is 2.5 km/s. Moment estimates range from 7.4 to 10.0×1024 dyn cm, depending on the rupture model.

Publication type Article
Publication Subtype Journal Article
Title Source complexity of the 1987 Whittier Narrows, California, earthquake from the inversion of strong motion records
Series title Journal of Geophysical Research Solid Earth
DOI 10.1029/JB095iB08p12475
Volume 95
Issue B8
Year Published 1990
Language English
Publisher American Geophysical Union
Description 11 p.
First page 12475
Last page 12485
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