Transient rheology of the oceanic asthenosphere following the 2012 Indian Ocean Earthquake inferred from geodetic data

Pratama, Cecep; Itô, Takeo; Sasajima, Ryohei; Tabei, Takao; Kimata, Fumiaki; Gunawan, E.; Ohta, Yusaku; Yamashina, Tadashi; Ismail, Nahed; Irwandi, Irwandi; Sugiyanto, Didik; Muksin, Umar; Meilano, Irwan

doi:10.1016/j.jseaes.2017.07.049

Cited by 24 publications

(5 citation statements)

References 43 publications

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“…The computation was conducted using an open-source FEM software PyLith [25][26][27] from Computational Infrastructure for Geodynamics (CIG). PyLith is widely used to simulate crustal deformation across spatial and temporal scales, especially for quasistatic and dynamic modeling earthquake faulting (e.g., [10,28,29]). PyLith implements fault slip using a domain decomposition approach with Lagrange multipliers.…”

Section: Methodsmentioning

confidence: 99%

Coseismic Deformation Responses due to Geometrical Structure and Heterogeneity of the Accretionary Wedge: Study Case 2010 Mentawai Earthquake, West Sumatra, Indonesia

Kuncoro

Srigutomo

Fauzi

2023

International Journal of Geophysics

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The assumption of a homogeneous elastic half-space model is widely used to model the earth’s deformation. However, the homogeneous assumption would not accurately reflect the complexity of the shallow crust. We performed a 3D coseismic deformation model using the finite element method and referred to the 2010 Mentawai earthquake. The 2010 tsunami earthquake was located at the Mentawai segment, which is a part of the accretionary wedge in the Sumatra subduction zone. This active accretionary wedge is identified as the most complicated structure on earth and lies along the Sumatra subduction zone, at which most destructive earthquakes happen in this region. We examined the impact of the accretionary wedge geometry and material properties by considering the wedge as a single different property separated from the continental plate. Various geometrical features, such as topography and wedge dimension, as well as physical properties, were simulated. Those features are then observed for their responses on the surface deformation. The topography affected the magnitude of the horizontal deformation up to 10% but only the pattern of the vertical deformation. The wedge dimension seems to have an insignificant influence on the surface deformation compared to the topography. Different physical properties of the accretionary wedge affect not only the magnitude of the horizontal deformation up to 40% but also the orientation. The direction of the lateral movement is seemingly affected by the material under the GPS station and by the source. On the other hand, the variations in the physical properties resulted in discrepancies of 0.5 meters in the vertical deformation near the source. These results indicated that regional physical property information and geometrical features are critical in estimating coseismic deformation, leading to more accurate slip inversion and earthquake and tsunami hazard prediction, particularly in regions with significant inhomogeneity.

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Section: Methodsmentioning

confidence: 99%

Coseismic Deformation Responses due to Geometrical Structure and Heterogeneity of the Accretionary Wedge: Study Case 2010 Mentawai Earthquake, West Sumatra, Indonesia

Kuncoro

Srigutomo

Fauzi

2023

International Journal of Geophysics

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“…The superiority of finite-element models (FEMs) in simulating the elastic dislocation and the viscoelastic relaxation with heterogeneous material properties has been proven by previous studies (Masterlark et al 2012;Hughes et al 2010;Hines et al 2016;Hsu et al 2013;Tung and Masterlark 2016;Pratama et al 2017). In the view of the strong topographical fluctuations and heterogeneity across the Himalayan region, the spherical FEM with topography and heterogeneity was constructed using the CUBIT software (Blacker et al 2016).…”

Section: Finite-element Modelmentioning

confidence: 99%

“…Because the FEM configuration used by Tung and Masterlark (2016) basically matched ours, we adopted the same refined coseismic rupture to drive viscoelastic relaxation. On the basis of that, we assigned the same fault geometry with a planar patch centered at (27.95° N, 85.27° E) with a dip and strike of 10° and We performed the calculation with the finite element software PYLITH (Aagaard et al 2013), which was widely applied to postseismic deformation modeling (Hines et al 2016;Pratama et al 2017) and to generate the Green's function (Diao et al 2014;Hsu et al 2013;Hines et al 2016).…”

Section: Finite-element Modelmentioning

confidence: 99%

“…Material heterogeneity affects surface deformation due to fault slip (Masterlark et al 2001(Masterlark et al 2003Hughes et al 2010;Kyriakopoulos et al 2013;Wiseman et al 2015;Tung and Masterlark 2016;Hu et al 2016;Klein et al 2016;Hsu et al 2014;Hines et al 2016;Pratama et al 2017;Suito 2017;Freed et al 2017). Therefore, the homogenous or layered earth model assumption for the Himalayan range, which has strong variations in material properties (Cattin et al 2001;Monsalve et al 2006;Schul.te-Pelkum et al 2005), inevitably introduces bias into the modeling (Kyriakopoulos et al 2013;Tung and Masterlark 2016;Suito 2017;).…”

Section: Introductionmentioning

confidence: 99%

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Probing time-dependent afterslip and viscoelastic relaxation following the 2015 Mw7.8 Gorkha earthquake based on the 3-D finite-element model

Shi

Gan

et al. 2020

Earth Planets Space

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We analyzed daily displacement time series from 34 continuous GPS stations in Nepal and 5 continuous GPS stations in South Tibet, China, and extracted the first 4.8 years of postseismic motion after the 2015 Mw7.8 Gorkha earthquake. With the longer duration GPS observations, we find that postseismic displacements mainly exhibit southward and uplift motion. To study the postseismic afterslip and viscoelastic relaxation, we built a 3-D spherical finite-element model (FEM) with heterogeneous material properties and surface topography across the Himalayan range, accounting for the strong variations in material properties and surface elevation along the central Himalayan arc. On the basis of the FEM, we reveal that the predicted viscoelastic relaxation of cm level moves southward to the north of the Gorkha earthquake rupture, but in an opposite direction to the observed postseismic deformation in the south; the postseismic deformation excluding viscoelastic relaxation is well explained by afterslip downdip of the coseismic rupture. The afterslip is dominant during 4.8 years after the 2015 Mw7.8 Gorkha earthquake; the contribution by the viscoelastic relaxation gradually increases slightly. The lack of slip on a shallow portion and western segment of the MHT during and after the 2015 Gorkha earthquake implies continued seismic hazard in the future.

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“…During the earthquake cycle, which is generally divided into deformations in three phases interseismic (Hanifa et al, 2014;Ohkura et al, 2015), coseismic (Ito et al, 2016;Gunawan et al, 2017a), and postseismic (Anugrah et al, 2015;Pratama et al, 2017) surface deformation can be observed using various geodetic tools. Modern equipment, such as the Global Positioning System (GPS; Alif et al, 2016), Interferometric Synthetic Aperture Radar (InSAR; Tung and Masterlark, 2016), and/or levelling (Murase et al, 2016), has been widely used to analyze crustal deformations and tectonic conditions in a region.…”

Section: Introductionmentioning

confidence: 99%

Coseismic and postseismic deformation from the 2007 Bengkulu earthquake based on GPS Data

Meilano¹,

Susilo

Gunawan

et al. 2021

Ris.Geo.Tam

Self Cite

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On September 12, 2007, a M8.5 megathrust earthquake occurred along the Sunda trench near Bengkulu, West Sumatra. GPS data in Sumatra have indicated the coseismic and postseismic deformations resulting from this earthquake. Our estimate of coseismic displacements suggests that the earthquake displaced up to ~1.8m at GPS stations located north of the epicenter. Moreover, our principal strain estimation in the region suggests that the maximum coseismic extensional strain is ~40 ppm. Our analysis of GPS data in the region suggests that the postseismic decay of the 2007 Bengkulu earthquake was 46 days, estimated using a logarithmic function.

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Transient rheology of the oceanic asthenosphere following the 2012 Indian Ocean Earthquake inferred from geodetic data

Cited by 24 publications

References 43 publications

Coseismic Deformation Responses due to Geometrical Structure and Heterogeneity of the Accretionary Wedge: Study Case 2010 Mentawai Earthquake, West Sumatra, Indonesia

Coseismic Deformation Responses due to Geometrical Structure and Heterogeneity of the Accretionary Wedge: Study Case 2010 Mentawai Earthquake, West Sumatra, Indonesia

Probing time-dependent afterslip and viscoelastic relaxation following the 2015 Mw7.8 Gorkha earthquake based on the 3-D finite-element model

Coseismic and postseismic deformation from the 2007 Bengkulu earthquake based on GPS Data

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