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Determining dislocation Love numbers using satellite gravity mission observations

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Abstract

This paper presents a new approach to calculate dislocation Love numbers using observations of a satellite gravity mission (e.g. GRACE). The necessary condition is that the co-seismic potential change be sufficiently large to be detected by the gravity mission. Co-seismic deformations for each spherical harmonic degree n are decoupled. Therefore, dislocation Love numbers of degree n can be determined independently. The determinable maximum harmonic degree n depends on the seismic size, source type, magnitude, and the accuracy of a satellite gravity mission. For an arbitrary seismic source, all four types of dislocation Love numbers can be determined using data from only one seismic event because all deformation components are involved together. Only the concerned dislocation Love numbers can be computed for any one of the four types of sources. To prove the validity of the method proposed in this study, a simulation test is carried out by considering a similar case to the 2004 Sumatra earthquake (Mw 9.1). Results show that the method works well and guarantee the accuracy.

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Correspondence to Wenke Sun.

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Sun, W., Okubo, S. & Sugano, T. Determining dislocation Love numbers using satellite gravity mission observations. Earth Planet Sp 58, 497–503 (2006) doi:10.1186/BF03351946

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Key words

  • Co-seismic deformation
  • dislocation Love number
  • gravity mission
  • earthquake GRACE
  • Sumatra earthquake