用接收函数研究川滇地区国家地震台下地壳厚度及波速比

本文利用远震接收函数的方法,对川滇地区的昆明、腾冲、成都和攀枝花等4个国家地震台的台基下方不同方向的莫霍面深度及波速比进行了研究和分析。结果表明:昆明地震台台基下方的莫霍面深度基本在50km左右,波速比为1.62～1.69,地壳厚度和波速比不因方向不同而发生明显的变化;腾冲地震台台基下方的地壳厚度有着比较明显的方向性,东北方向厚为40.7km,东南方向为49.7km,两个方向的波速比相差也很大,差值达到0.2;成都地震台台基下方莫霍面的深度在40km左右,但是东北和西南方向要加深8km,两个方向波速比相差0.13;攀枝花地震台台基下方的地壳厚度比较稳定,厚度在60km左右,波速比变化也不明显。

Crustal Thickness and Velocity Ratio Beneath National Seismic Stations in the Sichuan.Yunnan Area in Terms of Receiver Function

Teleseismic receiver function method is used in this paper to research on the Moho depths and v_p/v_s ratios of the 4 National seismic stations(KMI,TNC,CD2 and PZH)in the Chuandian(Sichuan-Yunnan)area.The study gives the Moho depths and velocity ratios of the four stations in different directions.The results show that,the Moho depth beneath the Kunming Station is around 50km,and the velocity ratio is between 1.62 and 1.69.The thickness of crust and the velocity ratio do not change with the direction.The Moho depths of Tengchong Station is of directivity with 40.7km in northeast,and 49.7 in southeast.The difference of the v_p/v_s values is remarkable between the two directions,which reaches 0.2.Chengdu Station also has shallow Moho depths,which is about 40km,but in the northeast and southwest it is 8km deeper.The velocity ratio has 0.13 difference.The thickness of crust beneath the Panzhihua Station is stable.In all directions,the Moho depth is around 60km and the v_p/v_s values also don't have much difference.