The Crustal Thickness and Poissons Ratio Distribution in Guangdong and Its Adjacent Areas

摘要

Based on the teleseismic waveform data recorded by 82 permanent broadband stations in Guangdong Province and its adjacent areas including Fujian,Jiangxi,Hunan,Guangxi,Hainan and Taiwan,we calculate body wave receiver functions under all stations,and obtain the crustal thickness and average Poissons ratio beneath all stations by the H-κstacking-search method of receiver function. The results show that the crustal thickness with an average thickness of 29. 5km in Guangdong Province and its adjacent areas ranges between 26. 8km and 33. 6km and gradually thins from northwest to southeast. The crustal thickness in the Zhujiang Delta, western Guangdong, Nanning and Nanao areas is relatively thinner and ranges between 25. 0km and 28. 0km. The minimum crustal thickness is about 26 km beneath Wengtian, Hainan and the Zhanjiang zone and Shangchuan Island in Guangdong. The crustal thickness in the zones of Mingxi,Fujian and Yongzhou, Hunan is thicker and varies between 31. 0km and 34. 0km. The distribution of Poissons ratio in our study region ranges between 0. 20 and 0. 29. Poissons ratios in Southeast Hainan,the coastal areas of East Guangdong and West Fujian and the South Jiangxi have distinctly higher values than in others. It suggests that the various geothermal fields located in these areas have high heat flow values. The distribution of crustal thickness and Poissons ratio has an obvious block feature and may be related to the distribution of faults and historical earthquakes.