ON THE INTERPRETATION OF THE DSS DATA OF SUIXIAN-ANYANG PROFILE IN CENTRAL CHINA

In this paper preliminary results of the interpretation of DSS data of the Suixian—Anyang profile are presented.The results show that the depth oif the Moho interface reaches 28 to 36 km in this region, and the average velocity in the crust here is about 6.24 km/s. The Mohb is deeper near the Qixian and Xinzheng counties. The velocity in the sedimentary layer is about 3.50 km/s, which is much thicker near the Yellow River (5 or 5.5 km). In the southern part of the profile there are granites and metamorphic rocks on the surface. The velocity of head waves near the upper boundary of crystalline basement is about 6.00 km/s. Three interfaces can be traced between this boundary and the Moho. They are P₂,P⁰₃ and P⁰₄; among these the P⁰₃ is more stable. It is the reflection from an interface in the crust. The average velocity in it is 5.97 km/s, and its depth varies from 18 to 23 km. Aseismic cross-section is also presented. Distinct features about the inhomogeneity of velocity and the gradient layer in the crust near the Yellow River between Xinzheng and Xinxiang have been noticed.We have also investigated the velocity distribution in the sedimentary layers near Xinxiang and the position of the fault near Wuyang according to the data of the diffracted phases. There is possibility of the existence of intercalary layers with high velocity in the upper mantle of this region.