The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Zhouchuan Huang - One of the best experts on this subject based on the ideXlab platform.
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p wave tomography anisotropy and seismotectonics in the Eastern Margin of japan sea
Tectonophysics, 2010Co-Authors: Zhouchuan Huang, Dapeng Zhao, Norihito Umino, Liangshu Wang, Toru Matsuzawa, Akira Hasegawa, Takeyoshi YoshidaAbstract:Abstract To understand the seismotectonics in the Eastern Margin of the Japan Sea, we determined the first high-resolution 3-D P-wave velocity structure and azimuthal anisotropy under the Japan Sea off Northeast Japan using 175,425 high-precision P-wave arrival times from 2833 local earthquakes recorded by 330 seismograph stations. P-wave arrival times from 145 suboceanic earthquakes relocated with sP depth phase are crucial to determine the structure of the crust and uppermost mantle under the Japan Sea. Our results show that strong velocity variations exist in the crust and uppermost mantle under the Eastern Margin of the Japan Sea. Many large crustal earthquakes occurred in or around low-velocity zones which may represent weak sections of the seismogenic crust. The P-wave azimuthal anisotropy is complex under the Japan Sea, which may also indicate the complex crustal structures there. In the Eastern Margin of the Japan Sea, the strong heterogeneities in the crust and upper mantle revealed by seismic tomography may reflect the complicated geologic structures such as the alternate rift zones, ridges, basins, horsts, grabens, volcanics, and continental fragments which were produced during the back-arc spreading, opening of the Japan Sea and the present compressional stage of the Honshu arc.
Takeyoshi Yoshida - One of the best experts on this subject based on the ideXlab platform.
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p wave tomography anisotropy and seismotectonics in the Eastern Margin of japan sea
Tectonophysics, 2010Co-Authors: Zhouchuan Huang, Dapeng Zhao, Norihito Umino, Liangshu Wang, Toru Matsuzawa, Akira Hasegawa, Takeyoshi YoshidaAbstract:Abstract To understand the seismotectonics in the Eastern Margin of the Japan Sea, we determined the first high-resolution 3-D P-wave velocity structure and azimuthal anisotropy under the Japan Sea off Northeast Japan using 175,425 high-precision P-wave arrival times from 2833 local earthquakes recorded by 330 seismograph stations. P-wave arrival times from 145 suboceanic earthquakes relocated with sP depth phase are crucial to determine the structure of the crust and uppermost mantle under the Japan Sea. Our results show that strong velocity variations exist in the crust and uppermost mantle under the Eastern Margin of the Japan Sea. Many large crustal earthquakes occurred in or around low-velocity zones which may represent weak sections of the seismogenic crust. The P-wave azimuthal anisotropy is complex under the Japan Sea, which may also indicate the complex crustal structures there. In the Eastern Margin of the Japan Sea, the strong heterogeneities in the crust and upper mantle revealed by seismic tomography may reflect the complicated geologic structures such as the alternate rift zones, ridges, basins, horsts, grabens, volcanics, and continental fragments which were produced during the back-arc spreading, opening of the Japan Sea and the present compressional stage of the Honshu arc.
Zhongxian Huang - One of the best experts on this subject based on the ideXlab platform.
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Ambient noise Love wave tomography in the Eastern Margin of the Tibetan plateau
Tectonophysics, 2010Co-Authors: Chunyong Wang, Zhongxian HuangAbstract:Abstract We collected continuous waveform data from June to December 2007 recorded by 49 broadband seismic stations in western Sichuan and Eastern Tibet, and applied an ambient noise technique to obtain a high-resolution tomography model of the crust beneath the Eastern Margin of the Tibetan plateau. Cross-correlations of ambient noise data are calculated in one-hour segments and stacked over 7 months. Then Love wave group dispersion curves along approximately 700-station pairs were determined using the multiple-filter analysis method. The study region was divided into a grid of 0.2° × 0.2°, and group velocity distribution maps between 8 and 40 s were obtained. The Love wave group velocity maps show good correlations with surface features. From the group velocity maps we inverted a 3-D model for SH wave velocity. The inferred SH velocity heterogeneities generally agree with variations in SV derived from Rayleigh wave dispersion, discrepancies between them are examined in view of non-uniqueness of the models and radial anisotropy. Both the Rayleigh and Love wave inversions show the significant difference of the crustal structure and reveal a prominent low-velocity zone within the mid-to-lower crust beneath the Eastern Margin of the Tibetan plateau.
Yu Jin - One of the best experts on this subject based on the ideXlab platform.
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Mapping the deep lithospheric structure beneath the Eastern Margin of the Tibetan Plateau from gravity anomalies
Journal of Geophysical Research, 2005Co-Authors: Xiaodian Jiang, Yu JinAbstract:[1] Various authors have investigated the mechanism of lateral support of the lithosphere in maintaining the uplift of the Tibetan Plateau, based on gravity data and elastic flexural modeling, in the south of the plateau across the Himalayas and in the north and the northwest across the Altyn Tagh and West Kunlun Shan. However, the degree of the regional compensation and lateral support to the east of the Tibetan Plateau has remained unknown. In this paper we present a lithospheric flexure model by interpreting gravity and topography to understand the first-order problem of lateral support of the lithosphere at the Eastern Margins of the Tibetan Plateau. The flexural modeling constrains the geometry and strength variation of the lithosphere from the Eastern Margin of Tibet past the Longmen Shan ranges on to the Sichuan Basin. A lithosphere of intermediate strength (Te = 45 km) beneath the Sichuan Basin is weakened (Te = 36 km) by the thrusting underneath the Eastern Margin of the Tibetan Plateau. The strength variations indicate that about 10 km of the crustal material of the lithosphere has been ripped off and integrated into the thickened, upper crust of the Tibetan Plateau, which, however, has no appreciable strength. The stiffness of the lithosphere keeps the Tibetan Plateau relatively stable at its Eastern Margin and enables the weight of the plateau to be supported in the east by the Sichuan. Lithospheric deformation in the southern Longmen Shan area is more pronounced than in the northern region.
Jiansi Yang - One of the best experts on this subject based on the ideXlab platform.
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asperity of the 2013 lushan earthquake in the Eastern Margin of tibetan plateau from seismic tomography and aftershock relocation
Geophysical Journal International, 2013Co-Authors: Baofeng Tian, Sha Liu, Jiansi YangAbstract:SUMMARY The Mw 6.6 Lushan earthquake occurred on 2013 April 20 in the Eastern Margin of Tibetan Plateau, and was about 50km away from the 2008 Mw 7.9 Wenchuan earthquake rupture zone. By using arrival times from portable and permanent seismic stations, local earthquake tomography and aftershock relocation were conducted by using 41955 first P and 42687 first S arrivals. Low-Vp/Vs, high-Vp and Vs anomaly are found in the source region, which is well consistent with the aftershock distributions. The ruptured fault plane might be a blind thrust and is well defined by the Vp/Vs structure and aftershock seismicity. High-velocity and lowVp/Vs anomalies may suggest the mafic or ultramafic materials thrust from mid-lower crust, and define the asperity that concentrated stresses responsible for seismogenesis. In contrast, low-Vs anomalyisfoundinthegapbetweentheWenchuanandLushanearthquakes,suggesting of ductile rocks with low stress.