中国地震科学实验场地震时空演变规律研究

Study on the temporal and spatial evolution of earthquakes in CSES

通过分析某一区域地震事件的时空演化过程可以了解该区域地震的演化特征,为评估该地区地震的危险性提供依据。基于中国地震科学实验场2000年至2019年3.0级以上的地震事件数据,利用加权平均中心、标准差椭圆和全局空间自相关等空间统计学方法探索该地区地震事件的时空演变规律。结果表明:(1)汶川地震之后该地区地震的发生频次总体呈现出下降趋势,地震的活动性逐渐减弱。(2)地震加权平均中心呈现出“折返”型的移动规律,在东北-西南方向上来回震荡。(3)地震事件的空间分布呈现“东北-西南”格局走向,与映秀-北川断裂带的方向基本一致。(4)该地区地震事件的空间分布模式以聚集模式为主,且正处于上升阶段,但上升速度较为缓慢。

We can master the evolution features of earthquakes in an area by analyzing the temporal and spatial evolution process of earthquake events in the certain area,which can provide a theoretical basis for evaluating the risk of earthquakes in this area.In this paper,we explore the temporal and spatial evolution law of earthquake events in this area by using the spatial statistical methods such as weighted average center,standard deviational ellipse and global spatial autocorrelation based on the data of earthquake events with magnitude 3.0 or larger from 2000 to 2019 in CSES.The results show that(1)After the Wenchuan earthquake,the frequency of earthquakes in this area shows the trend of falling down,and the earthquake activity has gradually weakened,(2)the weight average center of the earthquake shows a“turn-back”type movement law,which is constantly going back and forth from northeast to southwest,(3)the direction of spatial distribution of earthquakes shows a“northwest-southeast”pattern,which is basically consistent with the direction of the Yingxiu-Beichuan Fault,and(4)the spatial distribution pattern of earthquake events in this area is mainly clustering pattern,and it is in the rising stage,but the rising speed is relatively slow.