1976年以来南美板缘浅源强震间应力触发研究

Study on Stress Triggering of Strong Shallow-Focus Earthquakes in South America Since 1976

从全球CMT目录中选取南美板缘1976-01-01~2016-12-24期间M≥7.0浅源地震的震源机制解资料(共36次),应用Coulomb3.3软件计算先前地震在后续地震断层面上产生的静态库仑应力变化,探讨先前地震对后续地震是否有静态应力触发作用。结果表明,受到先前地震触发作用的地震数目为11个(以0.1bar为触发阈值),触发地震占比为31.4%,受到抑制的地震数目为7个,不确定的地震数目为17个,静态库仑应力变化为正的地震数目为22个,占比为62.9%,表明1976年以来南美板缘强震间存在一定的应力触发作用。

In this paper, we select the focal mechanism solution data of 36 shallow-focus earthquakes that satisfiesM≥7.0 from January 1, 1976 to December 24, 2016 on the south America plateau, drawing from the global CMT catalog. We use Coulomb3. 3 to calculate the static coulomb stress changes in the subsequent earthquake fault surface, and discuss whether there is a stress-triggered effect from previous earthquakes to subsequent earthquakes, The results show that, as the trigger threshold is 0.1 bar, 11 earthquakes are triggered by the previous earthquakes; the triggered earth- quakes are 31.4% of the total; there are 7 suppressed earthquakes and 17 uncertain earthquakes; 22 of the earthquakes have a positive static coulomb failure stress change, which accounts for 62.9% o- verall. Based on the research results above, we draw the conclusion that there have been some stress triggering effects between the south America plateau strong earthquakes since 1976.