[1]ZHANG Tianji,JIN Mingpei,LIU Zifeng,et al.Distribution and Significance of Crustal Thickness and Poisson's Ratio in Northwestern Yunnan[J].Journal of Seismological Research,2020,43(01):10-18.
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Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
43
Number of periods:
2020 01
Page number:
10-18
Column:
Public date:
2020-01-30
- Title:
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Distribution and Significance of Crustal Thickness and Poisson's Ratio in Northwestern Yunnan
- Author(s):
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ZHANG Tianji; JIN Mingpei; LIU Zifeng; CHENG Yuhao
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(Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)
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- Keywords:
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northwestern Yunnan; seismic meta-instability; receiver function; crustal thickness; Poisson's ratio
- CLC:
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P315.2
- DOI:
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- Abstract:
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Using teleseismic waveform data recorded by 43 stations in meta-instability observation experiment area of northwestern Yunnan from April 5 to December 30,2018,we calculated and analyzed the changes of crustal thickness and Poisson's ratio in northwestern Yunnan.The results showed:the crustal thicknesses in this area are generally the variation characteristics of deeper in north and shallower in south; the three areas of Yunlong,Hudiequan-Yanghe,and Yanqu-Yangwopeng-Shaoheng are mantle uplifting sites,and the Moho surface is characterized as a tongue shape protruding southward and basically featuring two uplifts and two depressions near 26°N.The Poisson's ratio ranges from 0.209 to 0.328 in the study area,which is divided into four quadrants by two diagonal lines,the north and south regions are high Poisson's ratios(σ>0.28),the crust maybe enriched with iron and magnesium; the west and east regions are low Poisson's ratios(σ<0.26),the crust maybe rich in felsic.Very high Poisson's ratios(σ>0.3)are found in Yunlong,Hudiequan-Yanghe,and Nanjian-Hongtupo areas maybe the partial melting of lower crustal material caused by the bottom intrusion of upper mantle material.The Tongdian-Jianji,Fengle-Hetou,and Maidi-Ziyangcun-Wayao-Taiyi-Chahe areas are high gradient zones of Poisson's ratio and are seismogenic environments with moderate to strong earthquakes.