Seismological constraints on the down-dip shape of normal faults

Reynolds, Kirsty and Copley, Alex (2017) Seismological constraints on the down-dip shape of normal faults. Geophysical Journal International, 213 (1). pp. 534-560. ISSN 0956-540X DOI https://doi.org/10.1093/gji/ggx432

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Abstract

We present a seismological technique for determining the down-dip shape of seismogenic normal faults. Synthetic models of non-planar source geometries reveal the important signals in teleseismic P and SH waveforms that are diagnostic of down-dip curvature. In particular, along-strike SH waveforms are the most sensitive to variations in source geometry, and have significantly more complex and larger-amplitude waveforms for curved source geometries than planar ones. We present the results of our forward-modelling technique for 13 earthquakes. Most continental normal-faulting earthquakes that rupture through the full seismogenic layer are planar and have dips of 30°–60°. There is evidence for faults with a listric shape from some of the earthquakes occurring in two regions; Tibet and East Africa. These ruptures occurred on antithetic faults, or minor faults within the hanging walls of the rifts affected, which may suggest a reason for the down-dip curvature. For these earthquakes, the change in dip across the seismogenic part of the fault plane is ≤30°.

Item Type:	Article
Uncontrolled Keywords:	2018AREP; IA74
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access 12 - PhD
Journal or Publication Title:	Geophysical Journal International
Volume:	213
Page Range:	pp. 534-560
Identification Number:	https://doi.org/10.1093/gji/ggx432
Depositing User:	Sarah Humbert
Date Deposited:	15 Mar 2018 23:36
Last Modified:	09 Jan 2019 13:35
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4130

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