[1]ZENG Xianwei,FENG Jiangang,LONG Feng,et al.Mid-upper Crustal Velocity Tomography of Pg Wave in Western Margin of Ordos[J].Journal of Seismological Research,2017,40(02):176-185.
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Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
40
Number of periods:
2017 02
Page number:
176-185
Column:
Public date:
2017-04-23
- Title:
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Mid-upper Crustal Velocity Tomography of Pg Wave in Western Margin of Ordos
- Author(s):
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ZENG Xianwei1; FENG Jiangang2; LONG Feng3; XIN Hailiang4
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(1. Earthquake Administration of Ningxia Hui Autonomous Region,Yinchuan 750001,Ningxia,China)(2. Earthquake Administration of Gansu Province,Lanzhou 730000,Gansu,China)(3. Earthquake Administration of Sichuan Province,Chengdu 610041,Sichuan,China)(4. Geophysical Exploration Center,Zhengzhou 450002,Henan,China)
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- Keywords:
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western margin of Ordos; mid-upper crust; velocity structure of Pg wave; moderate-strong earthquake
- CLC:
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P315.24
- DOI:
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- Abstract:
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In the paper,we obtained the inversion result of mid-upper crustal velocity tomography of Pg wave,station term perturbations and event term perturbations in western margin of Ordos,using 24 860 Pg wave rays of 5 370 earthquakes recorded by 30 seismic stations in the region. The results show that:(1)The mid-upper crustal velocity structure of Pg wave presents obvious lateral inhomogeneity. The stable Alashan block and Ordos block are mainly high speed regions,and there exist obvious high speed to low speed conversion on both border sides of the two blocks. The Yinchuan basin and Jilantai basin belong to relatively low velocity zone,and several major fault or fault segments belong to significant low velocity zone.(2)Since 1970,M≥5 moderate-strong earthquakes in the region mainly occurred in the high speed to low speed conversion zone. Therefore,the region where lateral velocity structure changes fiercely is that where earthquakes occur frequently.(3)In addition,the system travel time error caused by station base and clock correction is small. And,location error of earthquakes occurring in the surrounding region is larger than that occurring in the central region. It illustrates that the size of earthquake location error is closely related to the seismic station distribution.