[关键词]
[摘要]
利用广东及其邻域福建、江西、湖南、广西、海南、台湾共82个宽频带数字地震台的远震资料,计算获得了所有台站下方的体波接收函数,并通过接收函数H-κ搜索叠加方法反演了这些台站下方的地壳厚度和平均泊松比。研究结果表明,广东及其周边地区的地壳厚度为26.8~33.6km,平均为29.5km。由西北到东南逐渐变薄,表现出大陆地壳向大洋地壳的缓慢过渡过程。珠江三角洲、粤西、粤桂琼交界、广西南宁、广东南澳等地区地壳厚度较薄,为25.0~28.0km;海南的翁田、广东的湛江、上川岛等地壳厚度最薄,在26km左右;福建明溪、湖南永州周边地区地壳厚度较厚,为31.0~34.0km。研究区域内地壳泊松比为0.20~0.29,海南岛的东南部、粤东和闽西的沿海地区以及江西南部具有明显的高泊松比,这可能与这些地区具有广泛的温泉分布和高热流值的特性有关。地壳厚度和泊松比分布的分块特征明显,并与断层和历史地震的分布有关。
[Key word]
[Abstract]
Base on the teleseismic waveform data recorded by 82 permanent broadband stations in Guangdong Province and its adjacent areas including in Fujian,Jiangxi,Hunan,Guangxi, Hainan,and Taiwan,we calculated body wave receiver functions under all stations,and obtained the crustal thickness and averaged Poisson's ratio beneath these stations by the H-κ stackingsearch method of receiver function. The results show 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 Zhujiang Delta, western Guangdong,Nanning,and Nanao areas is relatively thinner and ranges between 25. 0km and 28. 0km. The minimum crustal thickness is about 26km beneath the Wengtian of Hainan and the Zhanjiang zone and Shangchuan Island of Guangdong. The crustal thickness in the zones of Mingxi,Fujian and Yongzhou,Hunan is thicker and varies between 31. 0 km and 34. 0 km. The distribution of Poisson's ratio in our study region ranges between 0. 20 and 0. 29. Poisson's ratio in southeast Hainan,the coastal areas of eastern Guangdong and western Fujian and southern Jiangxi has distinctly higher values than that in others. It suggests that the various geothermal fields are just located in these areas which have high heat flow values. The distribution of crustal thickness and Poisson's ratio have obvious block features and may be related to the distribution of faults and historical earthquakes.
[中图分类号]
[基金项目]
广东省科技计划项目(20090308)资助