腾冲火山区地壳结构的人工地震探测

DEEP SEISMIC SOUNDING OF CRUSTAL STRUCTURE IN TENGCHONG VOLCANIC AREA

介绍在腾冲地区完成的由一条近南北方向纵测线和两条近东西向的非纵测线组成的人工地震测深工程以及对纵测线资料解释的初步结果。上地壳的平均速度为 5 94km s ,其底界面深度为 12km左右 ;下地壳的平均速度为 6 6 7km s ,顶界面深度为 2 3km左右 ;中地壳可分为 2层 ,平均速度为 6 17km s ;纵测线的平均地壳厚度为 40km。在团田至腾冲之间的基底速度相当低 (5 80km s)。在腾冲与固东之间的中地壳界面有局部上拱现象。局部地区的地壳速度偏低以及壳内界面上拱可能与岩浆活动有关。

A project of deep seismic sounding,which consists of an in line profile with SN orientation and two off line profiles with EW orientation in Tengchong and its vicinity,and the preliminary results of crustal structure along the in line profile are described in this paper In upper crust,the average velocity is 5 94km/s,and the bottom depth is about 12km In lower crust,the average velocity is 6 67km/s,and the top depth is about 23km There is an average velocity is 6 17km/s in mid crust,which can be divided into 2 layers Crustal thickness along the in line profile is 40km on an average The basement in the region between Tuantian and Tengchong has a quite lower velocity(5 80km/s) Local arch interfaces in mid crust exist in the region between Tengchong and Gudong The lower crustal velocity and the intracrustal arch interfaces in local region are probably related to magma activity in the Tengchong volcanic area