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 Mw 7.8 earthquake. Issue 21 (8th November 2016)

• Record Type: Journal Article
• Authors: Li, Linyan; Cheung, Kwok Fai; Yue, Han; Lay, Thorne; Bai, Yefei
• Is Part Of: Geophysical research letters. Volume 43:Issue 21(2016)
• Page Start: 11, 182
• Page End: 11, 191
• Publication Date: 2016-11-08
• Subjects: dispersion -- joint inversion -- Mentawai earthquake -- finite fault -- tsunami; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL070970
• Languages: English
• ISSNs: 0094-8276

Abstract

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 Mw 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. Key Points: Modeling of tsunami generation from seafloor deformation leads to depth‐dependent attenuation and spreading of initial waves at the source Dispersion complements depth‐dependent tsunami excitation through lagging of short‐period components during trans‐oceanic propagation Including depth‐dependent tsunami excitation and dispersion in Green's functions produces larger and more concentrated slip through inversion