Global displacements caused by point dislocations in a realistic Earth model

Sun, Wenke; Okubo, Shuhei; Vaníček, Petr

doi:10.1029/95jb03536

Cited by 69 publications

(64 citation statements)

References 29 publications

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“…Note that the components of i j = 22 include two parts: m = 0 and 2; we here calculate and discuss only the deformations of m = 0: the computation of m = 2 can be derived easily from the component of i j = 12. Details can be found in Sun and Okubo (1993) or Sun et al (1996).…”

Section: Dislocation Love Numbers and Co-seismic Geoid And Gravity Chmentioning

confidence: 99%

Truncated co-seismic geoid and gravity changes in the domain of spherical harmonic degree

Sun

Okubo

2014

Earth Planet Sp

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A concept of truncated geoid and gravity changes is proposed in this study and corresponding truncated expressions are presented for investigating co-seismic deformations. Numerical investigations are carried out to observe whether or not co-seismic geoid and gravity changes are detectable by gravity satellite missions. Results of an individual harmonic degree or a summation to interested degrees are compared with the expected errors of the gravity missions, assuming a seismic source equivalent to the fault size of the Alaska earthquake (1964, m w = 9.2). Corresponding co-seismic deformations indicate that both the gravity and geoid changes are about two orders larger than the precision of GRACE. Based on these results, the minimum magnitudes of earthquakes detectable by GRACE are derived. The conclusion is that co-seismic deformations for an earthquake with a seismic magnitude above m = 7.5 (for the tensile sources) and m = 9.0 (for the shear sources) are expected to be detected by GRACE. Finally, a case study is made on the 2002 Alaska earthquake (m = 7.9). Results show that the co-seismic geoid and gravity changes are at or below the error level of GRACE, and are difficult to detect.

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Section: Dislocation Love Numbers and Co-seismic Geoid And Gravity Chmentioning

confidence: 99%

Truncated co-seismic geoid and gravity changes in the domain of spherical harmonic degree

Sun

Okubo

2014

Earth Planet Sp

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“…Results of global co- . Global horizontal displacements caused by the Sumatra-Andaman earthquake, as calculated by the spherical dislocation theory of (Sun et al, 1996) and the seismic waveform inversion fault model of (Ammon et al, 2005). The red lines show the contour of the amplitude of the horizontal displacements; blue lines indicate their directions.…”

Section: Introductionmentioning

confidence: 99%

“…A dislocation theory for a spherical earth is necessary to model the global coseismic displacements and to interpret the observed ones. This study adopts the quasi-static dislocation theory of (Sun et al, 1996) for a spherically symmetric earth model to calculate global co-seismic displacements. For the Sumatra event, several new fault models with a heterogeneous slip distribution have been published (Yamanaka, 2004;Ammon et al, 2005;Banerjee et al, 2005;Vigny et al, 2005), which can serve as input for segment-summation scheme by (Fu and Sun, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Global co-seismic displacements caused by the 2004 Sumatra-Andaman earthquake (Mw 9.1)

Sun

2006

Earth Planet Sp

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This paper presents and discusses the global co-seismic displacements caused by the 2004 Sumatra-Andaman earthquake, using quasi-static dislocation theory for a spherically symmetric earth model (Sun et al., 1996). Theoretical calculations are performed with a heterogeneous slip distribution fault model based on Ammon et al. (2005). Results show that the co-seismic horizontal displacements are large to the north-east and southwest of the fault plane. Even as far as 6000 km from the epicenter, more than 1 millimeter co-seismic horizontal displacements raised from the earthquake. This paper has three contributions: to validate the fault model (Ammon et al., 2005) by geodetic data; to interpret the displacements observed by GPS; and to provide a reference for other researchers or for other geodetic applications. Overall, the modelled and observed displacements basically agree with each other in both the near field and far field. The calculated displacements are a generally smaller than the observed ones, since considerable moment is released by slow-slips and/or aftershocks which has not been included in the fault model.

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“…Furthermore, to consider the effect of curvature and layer structure, Sun et al (1992Sun et al ( , 1996Sun et al ( , 2003Sun et al ( , 2004 and Sun and Okubo (1993, 1998, 2002 proposed a dislocation theory for a spherically symmetric, non-rotating, perfectly elastic and isotropic (SNREI) Earth model to compute co-seismic deformations, such as potential, gravity, geoid, and strain changes. Recently, and Fu and Sun (2007) investigated co-seismic deformations for a three-dimensional inhomogeneous earth model.…”

Section: Introductionmentioning

confidence: 99%

A Feasibility Study of an FEM Simulation Used in Co-Seismic Deformations: A Case Study of a Dip-Slip Fault

Lin¹,

Sun²,

Zhang³

et al. 2013

Terr. Atmos. Ocean. Sci.

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For this study, we conducted a numerical simulation on co-seismic displacement for a dip-slip fault in a half-space medium based upon a finite element method (FEM). After investigating technical problems of modeling, source and boundary treatment, we calculated co-seismic deformation with consideration to topography. To verify the numerical simulation results, the simulated co-seismic displacement was compared with that calculated using a dislocation theory. As a case study, considering the seismic parameters of the 2008 Wenchuan earthquake (M 8.0) as a source model, we calculate the co-seismic displacements with or without consideration of the terrain model in the finite element model to observe terrain effects on coseismic deformation. Results show that topography has a non-negligible effect on co-seismic displacement, reaching from -11.59 to 4.0 cm in horizontal displacement, and from -3.28 to 3.28 cm in vertical displacement. The relative effects are 9.05 and 2.95% for horizontal and vertical displacement, respectively. Such a terrain effect is sufficiently large and can be detected by modern geodetic measurements such as GPS. Therefore, we conclude that the topography should be considered in applying dislocation theory to calculate co-seismic deformations.

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Global displacements caused by point dislocations in a realistic Earth model

Cited by 69 publications

References 29 publications

Truncated co-seismic geoid and gravity changes in the domain of spherical harmonic degree

Truncated co-seismic geoid and gravity changes in the domain of spherical harmonic degree

Global co-seismic displacements caused by the 2004 Sumatra-Andaman earthquake (Mw 9.1)

A Feasibility Study of an FEM Simulation Used in Co-Seismic Deformations: A Case Study of a Dip-Slip Fault

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