Abstract: On the basis of analyzing regional earthquake activities and tectonic surroundings and analyzing seismic source rupture characteristics from GDSN broadband waveform data,combining the aftershock data,this paper discusses the relation of source rupture with aftershock distribution for nine earthquakes from 1988 to 1990 in Sichuan and Qinghai region,analyzes the migration of seismic radiated energy,studies the general pattern of earthquake activities since 1970 by Single link cluster (SLC) method,and discusses the tectonic movement background and geodynamic meaning in Sichuan Qinghai Xizang zone. The results show that the source features of these earthquakes are correspnding to the tectonic stress background. Sources of Qinghai earthquakes,however,all have apparent reverse slip components which are different from the strike slip source results of the researches in the past. And what those P axes of sources of Sichuan earthquakes basically are not near to horizontal direction is related to the local“Y”style of complicated tectonics.

Key words: Seismicity, Source characteristics, Earthquake migration, Sichuang, Qinghai, Xizang, Single-link cluster

摘要： 在分析区域地震活动和构造环境及利用GDSN的宽频带波形资料分析震源破裂特征的基础上,结合余震资料,讨论了1988～1990年发生在四川和青海的9次强震的震源破裂和余震分布特征,分析了四川、青海、西藏相邻区域内的地震能量迁移,并用单键群分析方法对1970年以来的地震活动总体图象进行了研究。结果表明,这些地震的震源性质与构造应力环境相符,但青海地震的震源都具有较大的逆掩分量,与过去的走滑震源性质不同,而四川地震的震源P轴不接近水平方向与当地的“Y”字形复杂构造有关。

关键词: 地震活动性, 震源特征, 地震迁移, 四川, 青海, 西藏, 单键群