Research on the Crustal Velocity Model of the Yunnan Region and Its Application

Volume 3, Issue 2, April 2019     |     PP. 13-27      |     PDF (536 K)    |     Pub. Date: November 25, 2019
DOI:    209 Downloads     6457 Views  

Author(s)

Yang Jingqiong, Yunnan Earthquake Agency,Kunming 650203,China
Yang Zhousheng, Yunnan Earthquake Agency,Kunming 650203,China
Zhang Huiyuan, Yunnan Earthquake Agency,Kunming 650203,China

Abstract
This paper selects the records of 7,412 earthquakes,each recorded by more than 10 stations in Yunnan between 2009 and 2014 to acquire the traveltime curves. Meanwhile, for improving precision,linear analysis,reduced traveltime curve and interval stability analysis are conducted focusing on the records of 83 earthquakes with ML≥3.0 recorded each by ≥80% of the stations,and by combining predecessors' research results,the initial crustal velocity model of the study area is obtained. By selecting 200 earthquakes with M≥ 3.0 occurring in Yunnan between 2010 and 2014,using the Hyposat batch location processing method to iterate the initial velocity model,and performing fitting to S waves layered velocity structure,we obtain the crustal velocity model for the Yunnan region, namely,the 2015 Yunnan model,with: v_(P1) =6.01km/s,v_(P2) =6.60km/s,v_(Pn) =7.89km/s, H_1 = 20km,H_2 = 21km,v_(S1) = 3.52km/s,v_(S2) = 3.86km/s,v_(Sn) = 4.43km/s. Analysis on earthquake relocations based on the new model shows that most earthquakes occurring in Yunnan are at a depth of 10km - 20km of the upper crust. The March 10,2011 MS5.8 Yingjiang and August 3,2014 M_S6.5 Ludian earthquakes are relocated,and the focal depths determined with the new model are respectively close to the precise positioning result and hypocentral distance to the strong motion stations at the epicenters,indicating that the new one-dimensional velocity model can better reflect the average velocity structure of the study area.

Keywords
The Yunnan area; Crustal velocity model; Earthquake location

Cite this paper
Yang Jingqiong, Yang Zhousheng, Zhang Huiyuan, Research on the Crustal Velocity Model of the Yunnan Region and Its Application , SCIREA Journal of Geosciences. Volume 3, Issue 2, April 2019 | PP. 13-27.

References

[ 1 ] Bai Zhiming,Wang Chunyong. Tomographic investigation of the upper crustal structure and seismotectonic environments in Yunnan Province[J].Acta Seismologica Sinica,2003,25( 2) : 117-127 ( in Chinese with English abstract) .
[ 2 ] Cai Linsun,Li Xinglin. Geology of Yunnan Province [M]. In: Ma Lifang (Editor) . Beijing: Geological Publishing House,2002. 293- 300 ( in Chinese) .
[ 3 ] Deng Qidong,Xu Xiwei,Yu Guihua. The Zoning Characteristics and Genesis of Active Faults in Chinese Mainland [A]. In: Seismological Geology Specialized Committee,China Seismological Society (Editor) Study on Active Faults of China [G]. Beijing: Seismological Press,1994. 1- 14 ( in Chinese) .
[ 4 ] Fang Lihua,Wu Jianping,Zhang Tianzhong,Huang Jing,Wang Changzai,Yang Ting. Relocation of mainshock and aftershocks of the 2011 Yingjiang MS5. 8 earthquake in Yunnan [J]. Acta Seismologica Sinica,2011,332) : 262-267( in Chinese with English abstract) .
[ 5 ] He Zhengqin,Ye Tailan,Su Wei. 3-D velocity structure of the middle and upper crust in the Yunnan region, China [J]. Pure and Applied Geophysics,2005,162( 12) : 2355-2368.
[ 6 ] Hu Hongxiang,Lu Hanxing,Wang Chunyong,He Zhengqin,Zhu Liangbao,Yan Qizhong,Fan Yuexin,Zhang Guoqing,Deng Ying'e. Explosion investigation of the crustal structure in western Yunnan Province [J]. Acta Geophysica Sinica,1986,29(2):133-144 ( in Chinese with English abstract) .
[ 7 ] Hu Hongxiang,Gao Shiyu. The investigation of fine velocity structure of the basement layer of earth's crust in western Yunnan Region [J]. Earthquake Research in China,1993,19 (4) :356-363 ( in Chinese with English abstract) .
[ 8 ] Hu Hongxiang,Li Xueqing. Base Velocity Fine Structure of Menglian-Simao-Malong Section in the Yunnan Region[M]. In: Chen Yuntai,Kan Rongju,Teng Jiwen ( Editors) . Beijing: Maritime Press,1994. 100-106 ( in Chinese) .
[ 9 ] Hu Jiafu,Su Youjin,Zhu Xiongguan,Chen Yun. S-wave velocity and Poisson's ratio structure of crust in Yunnan and its implication [J]. Science in China ( Series D: Earth Sciences) ,2005,48(2):210- 218.
[ 10 ] Huang Jinli,Zhao Dapeng,Zheng Sihua. Lithospheric structure and its relationship to seismic and volcanic activity in Southwest China [J]. Journal of Geophysical Research,2002,107( B10): 2255.
[ 11 ] Huang Jing,Liu Xuejun,Su Youjin,Wang Baoshan. Imaging 3-D crustal P-wave velocity structure of western Yunnan with bulletin data [J]. Earthquake Science,2012,25(2):151-160.
[ 12 ] Li Yonghua,Wu Qingju,Tian Xiaobo,Zhang Ruiqing,Pan Jiatie,Zeng Rongsheng. Crustal structure in the Yunnan region determined by modeling receiver functions [J]. Chinese Journal of Geophysics,2009,52(1) :67 -80 ( in Chinese with English abstract) .
[ 13 ] Wang Chunyong,Mooney W. D. ,Wang Xili,Wu Jianping,Lou Hai,Wang Fei. Study on 3-D velocity structure of crust and upper mantle in Sichuan-Yunnan region,China [J]. Acta Seismologica Sinica,2002,24(1) : 116 ( in Chinese with English abstract) .
[ 14 ] Wang Fuyun,Zhang Xiankang,Chen Qifu,Chen Yong,Zhao Jinren,Yang Zhuoxin,Pan Suzhen. Fine tomographic inversion of the upper crust 3-D structure around Beijing [J]. Chinese Journal of Geophysics,2005,48(2):359-366 ( in Chinese with English abstract) .
[ 15 ] Wang Chunyong,Lou Hai,Wang Xili,Qin Jiazheng,Yang Runhai,Zhao Jinming. Crustal structure in Xiaojiang fault zone and its vicinity [J]. Earthquake Science,2009,22(4) :347-356.
[ 16 ] Wu Jianping,Ming Yuehong,Wang Chunyong. Source mechanism of small-to-moderate earthquakes and tectonic stress field in Yunnan Province [J]. Acta Seismologica Sinica,2004,26(5):457-465 ( in Chinese with English abstract) .
[ 17 ] Zhang Xiankang,Zhao Jinren,Zhang Chengke,Ren Qingfang,Nie Wenying,Cheng Shuangxi,Pan Suzhen, Tang Zhouqiong. Crustal structure at the northeast side of the Pamirs [J]. Chinese Journal of Geophysics,2002,45(5):665-671 ( in Chinese with English abstract) .
[ 18 ] Zhang Zhongjie,Bai Zhiming,Wang Chunyong,Teng Jiwen,Lü Qingtian,Li Jiliang,Sun Shanxue,Wang Xinzheng. Crustal structure of Gondwana- and Yangtze-typed blocks: an example by wide-angle seismic profile from Menglian to Malong in western Yunnan [J]. Science in China ( Series D: Earth Sciences) ,2005a,48(11) : 1828-1836.
[ 19 ] Zhang Tianzhong,Wu Bater,Huang Yuan,Jiang Changsheng. Effect of the data recorded at nearby stations on earthquake relative location [J]. Chinese Journal of Geophysics,2007,50 (4):1123- 1130 ( in Chinese with English abstract) .
[ 20 ] Zhang Zhongjie,Deng Yangfan,Teng Jiwen,Wang Chunyong,Gao Rui,Chen Yun,Fan Weiming. An overview of the crustal structure of the Tibetan plateau after 35 years of deep seismic soundings [J]. Journal of Asian Earth Sciences,2011,40(4) :977-989.
[ 21 ] Zhu Yuanqing,Xia Congjun,Li Ping. A PTD method a new method for determinating focal depth and its application [J]. Seismological and Geomangnetic Observation and Research,1997a,18 (3):21-29 ( in Chinese with English abstract) .
[ 22 ] Zhu Yuanqing, Zhao Zhonghe. Research on the new method to raise earthquake location accuracy [J]. Seismological and Geomangnetic Observation and Research,1997b,18(5):59 -67 ( in Chinese with English abstract) .