Crustal Structure In Chongqing And Adjacent Regiondetermined By Receiver Functions

Seismic wave,like X-ray,is a bright lamp to lighten the earth's interior,and is a messenger to lead to the earth's interior,said by Prince Boris Borisovich Galitzine,a prominent Russian physicist.Our study on the earth's interior structure mainly comes from observation and study of seismic wave.The seismic wave can penetrate the earth's deep place and carry the information of the earth's structure,which can be used by us to detect the earth's interior structure with high precision.Especially,the rapid development in the digital observation and the computer network technology in the past decades makes more scholars have the ability to analyze earthquake source process and to detect and inverted internal structure of the earth can be directly detected and inverted.The study on the crust thickness in Chongqing and its neighboring areas is also of significance.The author applied for more than 700 remote seismic waveform records recorded by 33 stations in the study area from 2008 to 2016 from the National Digital Network Backup Center.The teleseismic receiver function method was used to extract the function of the crustal thickness and the wave speed ratio by receiver function at the seismic station below the station network.From the data application process to the data processing process,in addition to the data selection and pick-up arrival time,all in the Linux system,complete in the form of perl scripts to solve the large amount of data,to deal with the difficult problem,data processing.The software uses the seismic analysis processing software GSAC software developed by the University of St.Louis.We obtained crustal thickness in the area by using receiver function method.The results show that crustal thickness ranges from 38.5 to 51.0KM.Station CHK in Northeast Chongqing has the largest crustal thickness,51.0 KM,and Station ROC in west of Chongqing has the thinnest crust,38.5 KM.On the line AA 'we set,the crust shallow velocity beneath the Sichuan basin is low.At the WUL station,there is a low-velocity anomaly at 8-10 KM below the station,and we infer that this thin low-velocity zone likely to be the detachment surface which caused the eastern Sichuan thin-skin fold structure.