首页|Constraint on the focal mechanism of the 2011 Tohoku earthquake from the radial modes

Constraint on the focal mechanism of the 2011 Tohoku earthquake from the radial modes

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  • 国家科技期刊平台
  • NETL
  • NSTL
  • 万方数据
  • 维普
Different from other normal modes of the Earth's free oscillation that depend on all the six components (Mrr,Mtt,Mpp,Mrt,Mrp,and Mtp)of the centroid moment tensor,the amplitudes of the radial modes depend on the Mrr component(e.g.,scalar moment(M0),dip(δ),and slip(λ))and hypocenter depth of the focal mechanism,and hence can be easily used to constrain these parameters of the focal mechanism.In this study,we use the superconducting gravimeter(SG)records after the 2011 Tohoku earthquake to analyze the radial modes 0S0 and 1S0.Based on the solutions of the focal mechanism provided by the GCMT and USGS,we can obtain the theoretical amplitudes of these two radial modes.Comparing the theoretical amplitudes with the observation amplitudes,it is found that there are obvious differences between the former and the latter,which means that the GCMT and USGS focal mechanisms cannot well represent the real focal mechanism of the 2011 event.Taking the GCMT solution as a reference and changing the depth and the three parameters of the Mrr moment,the scalar moment(M0)and the dip(δ)have significant influences,but the effects of the slip(λ)and the depth are minor.After comparisons,we provide a new constraint(M0=5.8±0.09 × 1022 N·m,δ=10.1±0.08°,λ=88°,and depth=20 km)for the focal mechanism of the 2011 event.In addition,we further determine the center frequency(1.631567 ±2.6e-6 mHz)and quality factor(2046.4±50.1)of the 1S0 mode.

Focal mechanismRadial modesGravity observation

Weikun Chen、Hao Ding

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School of Geodesy and Geomatics,Hubei LuoJia Laboratory,Wuhan University,Wuhan 430079,China

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaEducational Commission of Hubei Province of ChinaSpecial Fund of Hubei Luojia LaboratoryKey Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University

41974022421925312020CFA109220100002210204

2024

10.1016/j.geog.2023.04.002

大地测量与地球动力学(英文版)
中国地震局地震研究所

大地测量与地球动力学(英文版)

EI
影响因子：0.568
ISSN：1674-9847
年,卷(期)：2024.15(1)
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