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High-resolution backprojection at regional distance: Application to the Haiti M7.0 earthquake and comparisons with finite source studies

Meng, L. and Ampuero, J.-P. and Sladen, A. and Rendon, H. (2012) High-resolution backprojection at regional distance: Application to the Haiti M7.0 earthquake and comparisons with finite source studies. Journal of Geophysical Research B, 117 (B4). Art. No. B04313. ISSN 0148-0227. http://resolver.caltech.edu/CaltechAUTHORS:20120522-091623841

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Abstract

A catastrophic M_w7 earthquake ruptured on 12 January 2010 on a complex fault system near Port-au-Prince, Haiti. Offshore rupture is suggested by aftershock locations and marine geophysics studies, but its extent remains difficult to define using geodetic and teleseismic observations. Here we perform the multitaper multiple signal classification (MUSIC) analysis, a high-resolution array technique, at regional distance with recordings from the Venezuela National Seismic Network to resolve high-frequency (about 0.4 Hz) aspects of the earthquake process. Our results indicate westward rupture with two subevents, roughly 35 km apart. In comparison, a lower-frequency finite source inversion with fault geometry based on new geologic and aftershock data shows two slip patches with centroids 21 km apart. Apparent source time functions from USArray further constrain the intersubevent time delay, implying a rupture speed of 3.3 km/s. The tips of the slip zones coincide with subevents imaged by backprojections. The different subevent locations found by backprojection and source inversion suggest spatial complementarity between high- and low-frequency source radiation consistent with high-frequency radiation originating from rupture arrest phases at the edges of main slip areas. The centroid moment tensor (CMT) solution and a geodetic-only inversion have similar moment, indicating most of the moment released is captured by geodetic observations and no additional rupture is required beyond where it is imaged in our preferred model. Our results demonstrate the contribution of backprojections of regional seismic array data for earthquakes down to M ≈ 7, especially when incomplete coverage of seismic and geodetic data implies large uncertainties in source inversions.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2011JB008702DOIArticle
http://www.agu.org/pubs/crossref/2012/2011JB008702.shtmlPublisherArticle
ORCID:
AuthorORCID
Ampuero, J.-P.0000-0002-4827-7987
Additional Information:© 2012 American Geophysical Union. Received 24 July 2011; accepted 1 March 2012; published 24 April 2012. This research was supported by NSF grant EAR-1015704, by the Gordon and Betty Moore Foundation, and by the Southern California Earthquake Center, which is funded by NSF Cooperative Agreement EAR-0106924 and USGS Cooperative Agreement 02HQAG0008. This paper is Caltech Tectonics Observatory contribution 196 and Caltech Seismolab contribution 10073.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR-1015704
Gordon and Betty Moore FoundationUNSPECIFIED
Southern California Earthquake CenterUNSPECIFIED
NSFEAR-0106924
USGS02HQAG0008
Subject Keywords:Haiti earthquake; backprojection; regional distance; seismic array
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory196
Caltech Division of Geological and Planetary Sciences10073
Record Number:CaltechAUTHORS:20120522-091623841
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20120522-091623841
Official Citation:Meng, L., J.-P. Ampuero, A. Sladen, and H. Rendon (2012), High-resolution backprojection at regional distance: Application to the Haiti M7.0 earthquake and comparisons with finite source studies, J. Geophys. Res., 117, B04313, doi:10.1029/2011JB008702.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:31586
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:22 May 2012 17:57
Last Modified:17 Sep 2015 21:37

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