Low velocity zone of upper mantle and its effect on PdSwr phase related to 670 kmdiscontinuity

作     者：魏东平 周蕙兰 王志秋 

作者机构：Graduate School University of Science and Technology of China Beijing China Department of International Cooperation China Seismological Bureau Beijing China 

出 版 物：《Acta Seismologica Sinica(English Edition)》 (ACTA SEISMOLOGICA SINICA)

年 卷 期：2000年第13卷第1期

页      面：67-74页

核心收录：

学科分类：070801[理学-固体地球物理学] 07[理学] 0708[理学-地球物理学] 

基　　金：157WJ0704/9435811 49070191,49734150 

主　　题：low velocity zone discontinuity incident angle of seismic ray travel-time epicentral distance 

摘      要：This paper studied some properties of PdSwr phase related to 670 km discontinuities in detail, and theoretically processed a preliminary analysis to this phase. We discussed the relationships between the incident angle ih of PdSwr phase with its path, epicentral distance, travel-time and relative amplitude due to low velocity zone (LVZ) of upper mantle, and preliminarily pointed out the main characters of PdSwr phase recorded in seismogram. The PdSwr phase is concentrated in range of 13.5~96.5. When epicentral distance is greater than 33, the start point of PdSwr phase is relatively well distinguishable and could thus be determined more easily. When the epicentral distance is between 13.5 to 33, the triplication of PdSwr s travel-time curve could be slightly distinguished due to the low velocity zone and 220 km seismic velocity discontirluity of upper mantle. The relevant observed PdSwr phase should be in a more complex pattern and it should be more difficult to determine its start point