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Published November 16, 2016 | Published + Supplemental Material
Journal Article Open

Effects of dispersion in tsunami Green's functions and implications for joint inversion with seismic and geodetic data: a case study of the 2010 Mentawai M_W 7.8 earthquake

Abstract

Tsunami observations play an important role in resolving offshore earthquake slip distributions. Nondispersive shallow-water models are often used with a static initial sea surface pulse derived from seafloor deformation in computation of tsunami Green's functions. We compare this conventional approach with more advanced techniques based on a dispersive model with a static initial sea surface pulse and with the surface waves generated from kinematic seafloor deformation. These three sets of tsunami Green's functions are implemented in finite-fault inversions with and without seismic and geodetic data for the 2010 Mentawai M_w 7.8 tsunami earthquake. Seafloor excitation and wave dispersion produce more spread-out waveforms in the Green's functions leading to larger slip with more compact distribution through the inversions. The fit to the recorded tsunami and the deduced seismic moment, which reflects the displaced water volume, are relatively insensitive to the approach used for computing Green's functions.

Additional Information

© 2016 American Geophysical Union. Received 24 AUG 2016; Accepted 20 OCT 2016; Accepted article online 22 OCT 2016; Published online 8 NOV 2016. The IRIS data management center was used to access the seismic data from Global Seismic Network and Federation of Digital Seismic Network stations. The hr-GPS data were recorded by the SuGAr network jointly operated by the Earth Observatory of Singapore and the Indonesia Institute of Sciences. The GITEWS GPS buoy data in Mentawai were provided by the Badan Meteorology and Geofisika (BMKG), Indonesia. DART buoy data were obtained from the NOAA National Data Buoy Center. The digital elevation model is derived from the 30 arc sec General Bathymetric Chart of the Oceans compiled by the British Oceanographic Center; the 2 arc sec Digital Bathymetric Model of Badan Nasional Penanggulangan Bencana, Indonesia; 1 arc sec Shuttle Radar Topography Mission from German Aerospace Center; 0.15 arc sec LiDAR data at Padang from Badan Informasi Geospasial; and a 9 arc sec gridded data set in the Cocos Island region from Geoscience Australia. L. Li, Y. Bai, and K.F. Cheung received support from National Tsunami Mitigation Program grant NA15NWS4670025, T. Lay was supported by NSF grant EAR1245717, and H. Yue was supported by a Caltech Seismological Director's fellowship. We thank the two anonymous reviewers for the comments and suggestions that have improved this paper. SOEST contribution 9834.

Attached Files

Published - Li_et_al-2016-Geophysical_Research_Letters.pdf

Supplemental Material - grl55157-sup-0001-2016GL070970_S01.docx

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August 22, 2023
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