利用非线性方法反演琉球-台湾-吕宋地区的岩石层P波速度结构  

Inversion of P-wave velocity structure of lithosphere in the Ryukyu-Taiwan-Luzon area by nonlinear algorithm

作　　者：李志伟[1] 胥颐[1] 郝天珧[1] 刘劲松[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学进展》2007年第5期1345-1351,共7页Progress in Geophysics

基　　金：中国科学院知识创新项目(KZCX3-SW-234-2)资助

摘　　要：根据中国地震台网和ISC台站提供的P波走时资料,使用差异演化全局优化算法(DE算法)和移动窗方法反演了琉球-台湾-吕宋地区岩石层尺度的P波速度结构.在台站和地震分布较为密集的地区,反演窗口为2°×2°,移动步长为1°;在台站和地震较少的地区,反演窗口为4°×4°左右,移动步长为2°.反演结果揭示出琉球-台湾-吕宋地区壳幔结构的横向差异:琉球岛弧西侧受冲绳海槽地幔热扰动的地壳减薄,东侧由于菲律宾海板块的俯冲挤压地壳略有增厚;欧亚大陆与菲律宾海板块的相互碰撞导致台湾地区地壳及岩石层明显增厚;吕宋及菲律宾北部岩石层受岛弧火山下方热流影响较大.结果表明,非线性全局优化算法和移动窗方法能够用于反演较大尺度速度结构的横向变化.Using P wave travel-time data from the Chinese seismic networks and the ISC stations, we inversed P wave velocity structure of lithosphere in the Ryukyu-Taiwan-Luzon areas through the Differential Evolution Algorithm and moving window method. In the area with dense stations and earthquakes, the used moving window is 2^o× 2^o with 1^o intervals; in the area with sparse stations or earthquakes, the moving window is 4^o× 4^o with 2^o intervals. The result reveal obvious lateral variations of the lithosphere in the Ryukyu-Taiwan-Luzon areas： the crust in western Ryukyu is thinned due to strong thermal perturbation beneath the Okinawa Trough, while the crust in the eastern Ryukyu is thickened by the westward subduction and collision of Philippine Sea plate; the curst and lithosphere in the Taiwan ar- ea is also thickened due to the collision between the Eurasian continent and the Philippine Sea plate; the Luzon area is strongly affected by heat flow beneath island arc volcanoes. The result shows that this nonlinear algorithm is adequate to inverse lateral variation of velocity structures in large scales.

关 键 词：非线性算法 P波速度结构 岩石层结构 

分 类 号：P738[天文地球—海洋地质] P315[天文地球—海洋科学]