Geophysical Research Letters

Supporting Information for

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

Linyan Li1, Kwok Fai Cheung1,*, Han Yue2, Thorne Lay3, and Yefei Bai1

1Department of Ocean and Resources Engineering, University of Hawaii at Manoa, Honolulu, HI, USA.2Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, USA.3Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA.

*Corresponding author: Kwok Fai Cheung (cheung@hawaii.edu)

Contents of this file

Figures S1 to S6

Introduction

Supporting information to demonstrate convergence of tsunami Green's functions with

computational grid size and reduction of numerical oscillations in the hydrostatic results through

superposition and filtering.

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Figure S1. Convergence of Green's functions from subfault 10 at DART 56001. (a) Comparison between the H-S (black) and Nh-S (red) approaches. (b) Comparison between grid sizes of 0.5 (black), 1 (red), and 2 (blue) arc-min. The non-hydrostatic Green's functions converge rapidly with the computational grid size. The hydrostatic Green's functions contain the tsunami signals along with high-frequency numerical oscillations sensitive to the grid size. The numerical oscillations are caused by the limited resolution of short-period tsunami signals from the fine rupture grid.

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Figure S2. Comparison between linearly combined Green's functions (red lines) from subfaults 1 to 45 and NEOWAVE output (black lines) at the four water-level stations (a) through (d) from the H-S, Nh-S, and Nh-K approaches. The minor discrepancy between the superposed Green's functions and the NEOWAVE output at Cocos Island is related to nonlinearity over the shallow lagoon. The numerical oscillations in the hydrostatic results are reduced through the superposition due to longer period waves from a larger rupture area.

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Figure S3. Comparison between linearly combined Green's functions (red lines) from all 105 subfaults and NEOWAVE output (black lines) at the four water-level stations (a) through (d) from the H-S, Nh-S, and Nh-K approaches. The minor discrepancy between the superposed Green's functions and the NEOWAVE output at Cocos Island is related to nonlinearity over the shallow lagoon. The numerical oscillations in the hydrostatic results are reduced through the superposition due to longer period waves from a larger rupture area.

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Figure S4. Convergence of Green's functions from subfault 10 at DART 56001 with filtering of the hydrostatic results to remove signals below 3 min period. (a) Comparison between the H-S (black) and Nh-S (red) approaches. (b) Comparison between grid sizes of 0.5 (black), 1 (red), and 2 (blue) arc-min. The hydrostatic Green's functions show tsunami signals over a wide period range arriving simultaneously at the station due to the lack of dispersion.

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Figure S5. Horizontal components of recorded (red) and modeled (black) hr-GPS ground displacement signals from the joint inversion with non-hydrostatic tsunami Green's functions. The stations are ordered by epicentral distance.

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Figure S6. Recorded (red) and modeled (black) teleseismic waves from the joint inversion with non-hydrostatic tsunami Green's functions. The stations are ordered by azimuth.

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