1990年以来四川地区地震时空分布特征

Space –Time Distribution of Earthquake in Sichuan since 1990

以四川1990~2014年1445次M≥3的地震数据为基础,利用ArcGIS软件,进行空间分析中缓冲区分析,建立了断裂带10~20km缓冲区距离,编制四川断裂带背景下的分震级系列图谱,及分年际、分月际的图谱。通过对图谱的分析认为,研究区断裂带与该地区地震活动空间关系密切,地震活动主要集中于龙门山断裂分布区。时间上,1990年左右开始的地震活跃幕于2001年左右宣告闭幕,而2006年至今四川地区正处于新的活跃期,且地震活动频度和强度均增大,2002~2005年为两次活跃期过渡期。地震总次数和分震级地震在4、5、8月份均出现高值。

This study makes special analysis and buffer analysis of 1445 earthquakes with M〉3 in Sichuan during 1990-2014 by means of AreGIS, compiling a series of maps of earthquakes by magnitude in the background of the fault zone and a series of maps of earthquakes by years and months. The study indicates that the fault zones in this region are in close relationship to earthquakes, and earthquake activity centralize in the Longmenshan fracture zone. In the time, earthquake activity episode starting about 1990 was closed about 2001. Sichuan has been in a new earthquake activity episode since 2006, with increase in Frequency and intensity of seismic activity.