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| Detection and interpretation of the Earth’s free oscillations excited by the great Sumatra-Andaman earthquake with GGP station data |
| Xiang’e Lei, Heping Sun, Houtse Hsu |
| Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China |
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Abstract The mode serials of the Earth’s free oscillation provide some important information on the Earth’s deep structure and superconducting gravimeters (SG) can investigate the phenomena of the Earth’s free oscillations with high accuracy. The great Sumatra-Andaman earthquake fully excited the Earth’s free oscillations and these signals were perfectly recorded by five superconducting gravimeters in the globe. After the pre-treatment and spectral analysis on the SG observation data, we obtained the experimented mode serials of the Earth’s free oscillations consisting of 147 modes with GGP station data. These observed modes were themselves some new important data for the study of the Earth’s deep structure. On the basis of the discussions on some checked inner-core-sensitive modes, we distinguished three layers from the inner core, and the boundary of the upper layer was compatible with the formerly known transition zone in the inner core based on seismic body waves and supported that there were the hemispherical variation and very lower shear velocity zone in the lower inner core.
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Received: 19 September 2010
Published: 10 April 2011
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| Fund:the National Natural Science Foundation of China (Nos. 40974046, 90814009 and 40730316), the Natural Science Foundation of Hubei Province (No. 2008CDB389) and the Knowledge Innovation Project of Chinese Academy of Sciences (No. KZCX2-YW-133) |
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Corresponding Authors:
Xiang’e Lei
E-mail: leixe@whigg.ac.cn
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