High-resolution analysis of the gravest seismic normal modes after the 2004 Mw = 9 Sumatra earthquake using superconducting gravimeter data

S. Rosat; T. Sato; Y. Imanishi; J. Hinderer; Y. Tamura; H. McQueen; M. Ohashi

doi:10.1029/2005GL023128

High-resolution analysis of the gravest seismic normal modes after the 2004 M_w = 9 Sumatra earthquake using superconducting gravimeter data

S. Rosat^*, T. Sato, Y. Imanishi, J. Hinderer, Y. Tamura, H. McQueen, M. Ohashi

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

55 Citations (Scopus)

Abstract

The M_w > 9 Sumatra-Andaman earthquake on December 26, 2004 has strongly excited the low-frequency seismic modes and is a unique opportunity to improve the frequency and damping measurements of the gravest seismic modes. The precise estimation of the frequency splitting of the seismic modes below 1 mHz is needed to improve 1D-density models of the Earth. From this event, ₂S₁ is observed for the first time without any stacking on both SG (Superconducting Gravimeter) and seismic records. We report here analyses of SG data obtained from 11 sites. The spectra of SG records clearly show the splitting of ₀S₂ into 5 completely resolved singlets and the splitting of ₀S₃ into 7 singlets at individual stations. The present results demonstrate that SGs provide high quality data for a precise analysis of the low-frequency seismic modes.

Original language	English
Article number	L13304
Pages (from-to)	1-4
Number of pages	4
Journal	Geophysical Research Letters
Volume	32
Issue number	13
DOIs	https://doi.org/10.1029/2005GL023128
Publication status	Published - 1 Jul 2005

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abstract = "The Mw > 9 Sumatra-Andaman earthquake on December 26, 2004 has strongly excited the low-frequency seismic modes and is a unique opportunity to improve the frequency and damping measurements of the gravest seismic modes. The precise estimation of the frequency splitting of the seismic modes below 1 mHz is needed to improve 1D-density models of the Earth. From this event, 2S1 is observed for the first time without any stacking on both SG (Superconducting Gravimeter) and seismic records. We report here analyses of SG data obtained from 11 sites. The spectra of SG records clearly show the splitting of 0S2 into 5 completely resolved singlets and the splitting of 0S3 into 7 singlets at individual stations. The present results demonstrate that SGs provide high quality data for a precise analysis of the low-frequency seismic modes.",

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AU - Rosat, S.

AU - Sato, T.

AU - Imanishi, Y.

AU - Hinderer, J.

AU - Tamura, Y.

AU - McQueen, H.

AU - Ohashi, M.

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AB - The Mw > 9 Sumatra-Andaman earthquake on December 26, 2004 has strongly excited the low-frequency seismic modes and is a unique opportunity to improve the frequency and damping measurements of the gravest seismic modes. The precise estimation of the frequency splitting of the seismic modes below 1 mHz is needed to improve 1D-density models of the Earth. From this event, 2S1 is observed for the first time without any stacking on both SG (Superconducting Gravimeter) and seismic records. We report here analyses of SG data obtained from 11 sites. The spectra of SG records clearly show the splitting of 0S2 into 5 completely resolved singlets and the splitting of 0S3 into 7 singlets at individual stations. The present results demonstrate that SGs provide high quality data for a precise analysis of the low-frequency seismic modes.

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High-resolution analysis of the gravest seismic normal modes after the 2004 M_w = 9 Sumatra earthquake using superconducting gravimeter data

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