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     6141 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.

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