用转换函数方法研究腾冲—临沧地区地壳结构  

Crust structure beneath Tengchong-Lincang region,Yunnan province,revealed by transform function

作　　者：高星[1] 郭志[1] 王卫民[1] 姚振兴[2] 

机构地区：[1]中国科学院青藏高原研究所,北京100085 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学报》2008年第2期451-459,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(40674073,40404003,40034010);国家973项目(2005CB422)资助

摘　　要：根据流动数字地震台网提供的三分量地震波形记录资料，应用转换函数及快速模拟退火算法对腾冲一临沧地区30个地震台站下的地壳横波速度结构进行了反演．反演结果说明，研究区壳幔边界清晰、莫霍界面附近速度跳跃明显，由此得出该区地壳厚度在40km左右、并具有从南向北增厚趋势．一个普遍的现象是，在腾冲一宝山地块下地壳存在明显的低速带，低速带的厚度在10～20km间．研究结果进一步表明各台站下方上地幔速度结构复杂．这些结果为探讨青藏高原东南缘下地壳的侧向黏性流动、碰撞板块边界处壳幔物质交换等均提供了重要的地球物理证据，为探讨印一藏汇聚过程中青藏高原东构造结岩石圈变形、高原隆升及其深部动力学有一定理论意义．Based on three-component teleseismic records from portable digital seismic stations deployed in the Tengchong-Lincang region of Yunnan province,the S-wave velocity structure beneath 30 teleseismic stations are inversed by using the transform function method and SA technique. The result shows that in the region the Swave velocities around the crust-mantle boundary and the velocity jump across the Moho discontinuity are clear, resulting in the mean thickness of the crust about 40 km with the tendency of northward increase. A common feature from the inversion result is that in the lower crust exists an obvious slow velocity zone about 10-20 km thick. Meanwhile, the velocity structure of the upper mantle below most stations is complex, suggesting that lithospheric deformation and material exchange between the crust and the upper mantle should exist near the India-Tibet collisional zone. Therefore, the presented result should provide new evidence for studying the lithospheric deformation and tectonic evolution around the Tengchong-Lincang region of the Southeastern Tibetan plateau, such as lower-crust channel flow model.

关 键 词：波形反演 速度结构 转换函数 模拟退火算法 

分 类 号：P315[天文地球—地震学]