【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-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-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-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.更多还原

【Abstract】 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 S-wave 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 the proposed lower-crust channel flow model.更多还原