The 2010 M_w 8.8 Maule, Chile earthquake: Nucleation and rupture propagation controlled by a subducted topographic high

Hicks, Stephen P, Rietbrock, Andreas, Haberland, Christian A, Ryder, Isabelle MA, Simons, Mark and Tassara, Andrés (2012) The 2010 M_w 8.8 Maule, Chile earthquake: Nucleation and rupture propagation controlled by a subducted topographic high Geophysical Research Letters, 39 (19). n/a-n/a. ISSN 0094-8276, 1944-8007

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Abstract

Knowledge of seismic properties in an earthquake rupture zone is essential for understanding the factors controlling rupture dynamics. We use data from aftershocks following the Maule earthquake to derive a three‐dimensional seismic velocity model of the central Chile forearc. At 36°S, we find a highvp (>7.0 km/s) and high vp/vs(∼1.89) anomaly lying along the megathrust at 25 km depth, which coincides with a strong forearc Bouguer gravity signal. We interpret this as a subducted topographic high, possibly a former seamount on the Nazca slab. The Maule earthquake nucleated at the anomaly's updip boundary; yet high co‐seismic slip occurred where the megathrust is overlain by lower seismic velocities. Sparse aftershock seismicity occurs within this structure, suggesting that it disrupts normal interface seismogenesis. These findings imply that subducted structures can be conducive to the nucleation of large megathrust earthquakes, even if they subsequently hinder co‐seismic slip and aftershock activity.

Item Type:	Article
Additional Information:	Issue date: 16 October 2012. First published online 13 October 2012. Cite as: Hicks, S. P., A. Rietbrock, C. A. Haberland, I. M. A. Ryder, M. Simons, and A. Tassara (2012), The 2010 Mw 8.8 Maule, Chile earthquake: Nucleation and rupture propagation controlled by a subducted topographic high, Geophys. Res. Lett., 39, L19308, doi:10.1029/2012GL053184. Pages not for citation. 6 pages.
Uncontrolled Keywords:	Earthquake rupture, subduction, nucleation, SEISMIC GAP, TOMOGRAPHY, SLIP
Subjects:	?? QE ??
Divisions:	Faculty of Science & Engineering > School of Environmental Sciences
Depositing User:	Symplectic Admin
Date Deposited:	04 Mar 2014 15:58
Last Modified:	07 Dec 2024 12:51
DOI:	10.1029/2012gl053184
Related Websites:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/16155
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