Rupture process of the 2010 M_w 7.8 Mentawai tsunami earthquake from joint inversion of near‐field hr‐GPS and teleseismic body wave recordings constrained by tsunami observations

Abstract

The 25 October 2010 Mentawai tsunami earthquake (M w 7.8) ruptured the shallow portion of the Sunda megathrust seaward of the Mentawai Islands, offshore of Sumatra, Indonesia, generating a strong tsunami that took 509 lives. The rupture zone was updip of those of the 12 September 2007 M w 8.5 and 7.9 underthrusting earthquakes. High-rate (1 s sampling) GPS instruments of the Sumatra GPS Array network deployed on the Mentawai Islands and Sumatra mainland recorded time-varying and static ground displacements at epicentral distances from 49 to 322 km. Azimuthally distributed tsunami recordings from two deepwater sensors and two tide gauges that have local high-resolution bathymetric information provide additional constraints on the source process. Finite-fault rupture models, obtained by joint inversion of the high-rate (hr)-GPS time series and numerous teleseismic broadband P and S wave seismograms together with iterative forward modeling of the tsunami recordings, indicate rupture propagation~50 km up dip and~100 km northwest along strike from the hypocenter, with a rupture velocity of~1.8 km/s. Subregions with large slip extend from 7 to 10 km depth~80 km northwest from the hypocenter with a maximum slip of 8 m and from~5 km depth to beneath thin horizontal sedimentary layers beyond the prism deformation front for~100 km along strike, with a localized region having >15 m of slip. The seismic moment is 7.2 × 10 20 N m. The rupture model indicates that local heterogeneities in the shallow megathrust can accumulate strain that allows some regions near the toe of accretionary prisms to fail in tsunami earthquakes.

Tsunami evacuation plans for future megathrust earthquakes in Padang, Indonesia, considering stochastic earthquake scenarios

“…The properties of the fault plane are consistent with the previous investigations. For instance, the depth is comparable with the source models of the past Mentawai-Sunda subduction earthquakes and the strike and dip angles are in line with the slab models of the Sunda subduction zone developed by the USGS (Newman et al, 2011;Satake et al, 2013;Philibosian et al, 2014;Yue et al, 2014;Hayes et al, 2009Hayes et al, , 2012. In addition, to stochastically generate the earthquake sources, the fault plane is divided into 10 km by 10 km sub-faults (see Fig.…”

“…Recently, several international organizations and consortia have produced global DEM datasets, including GTOPO30, SRTM30, SRTM3v2, SRTM3v4, SRTM1, and GDEM2. Currently, the SRTM1 (https://lta.cr.usgs.gov/SRTM1Arc) and GDEM2 (https://asterweb.jpl.nasa.gov/gdem.asp) with a resolution of 1 arcsec (∼ 30 m) are the best available global DEM datasets and widely used for land elevation data in tsunami simulation (Satake et al, 2013;Yue et al, 2014).…”

Near-field tsunami forecast system based on near real-time seismic moment tensor estimation in the regions of Indonesia, the Philippines, and Chile

“…3). Our SWIFT CMT solutions are in good agreement with the GCMT and USGS solutions except for the Mentawai tsunami earthquake that occurred on October 25, 2010 (e.g., Satake et al 2013;Yue et al 2014). …”

Application MuTsunami in Mentawai Island Indonesia

“…al, [9]. The computation was performed in affordable notebook computer, equipped with processor I5 2.7 GHz, 16GB Ram.…”

“…The 25 October 2010 Mentawai tsunami earthquake (Mw 7.8) ruptured the shallow portion of the Sunda megathrust seaward of the Mentawai Islands, offshore of Sumatra, Indonesia, generating a strong tsunami that took 509 lives [9]. They iteratively adjusted the data weighting, rupture velocity, spacing, and lateral extent of the finitefault model grid in the joint inversion of the hr-GPS and teleseismic signals to reproduce the tsunami observations through modeling of nonlinear and dispersive ocean wave processes.…”