THE STRUCTURE OF THE CRUST AND UPPER MANTLE IN THE SHUIXIAN-MAANSHAN ZONE AND SOME CHARACTERISTICS OF THE SOUTH PART OF THE TAN-LU TECTONIC BELT
ZHENG YE TENG JI-WEN(Institute of Geophysics,Academia Sinica Beijing)
Ill this paper, the data of explosion seismology are studied, which were obtained by the Institute of Geophysics, Academia Sinica in the Shuixian-Maanshan zone from 1979 to 1981. The travel-times and amplitudes of the phases of seismic waves were fitted respectively using the 2-D ray tracing method. The structures of the crust and upper mantle were obtained. The crust thickness varies from 32 to 37 km. The Moho discontinuity rises and falls apparently. The velocity of the crust varies clearly in lateral direction. There is a low-velocity layer in the mid-crust. Within an area of tens of kilometers across which is west to the Chaohu Lake, the structure of the crust differs from other areas. The Moho discontinuity has been raised and interrupted. Two faults exist at the sides of the area. Finally, the result is analysed and discussed combining with other characteristics of geophysical field and tectonics. It is suggested that the Tan-lu tectonic belt is composed of two faults and is tens of kilometers wide, and that the mantle material rose up in the tectonic belt in geological history.
【Fund】： 国家科学基金;; 中国科学院基金