论文部分内容阅读
本文根据区域台网的观测资料,研究了云南省龙陵地区1971年至1980年的小震平均节面解的变化特点。结果表明:1.1971年2月至1975年11月,平均节面解的P轴方位同北东—南西向的区域应力场一致;2.大震前半年和大震后两天的P轴方位变为340°和176°,同主震的P轴相一致;3.强余震前的小震平均节面解同强余震的节面解相似;4.1977年至1980年3月,P波初动符号的矛盾比上升到30％以上,在此期间本区未发生5级以上的地震。最后讨论了本文所得的结果及其前兆意义。
In this paper, based on the observation data of the regional network, the variation characteristics of small-mean-section-mean-section solutions in Longling area of Yunnan Province from 1971 to 1980 are studied. The results show that: 1. From February 1971 to November 1975, the P-axis orientation of the mean section solution coincides with the NE-NWW regional stress field; 2. The P-axis azimuth changes in the first half of the great earthquake and two days after the earthquake For 340 ° and 176 °, consistent with the P-axis of the main shock; 3. The mean section solution for small earthquakes before strong aftershocks is similar to that for the strong aftershocks; 4. From 1977 to March 1980, Up to more than 30%, during which no earthquakes of magnitude 5 or above occurred in this area. Finally, we discuss the results obtained in this paper and their precursory significance.