摘要
强地震发生前，区域地震活动往往出现应变释放加速（AMR）现象。本文以华北地区的l976年唐山7．8级地震、1998年张北6．2级地震、2006年文安5．1级地震作为目标地震，分别分析三次主震前4～8年期间、40～120km半径范围内的AMR现象及其特征。结果显示，唐山7．8级地震与张北6．2级地震之前均不同程度出现AMR异常，但文安5．1级地震之前并未出现。另外，本研究发现80km半径可能是研究区寻找AMR异常有效、合理的空间扫描尺度。基于这三个震例研究的认识，本文进一步针对晋冀蒙交界地区和首都圈地区进行分析计算，结果识别m首都圈地区至目前存在AMR异常地区，这可作为判定华北北部未来强震危险性的参考。
For regional seismicity the phenomenon of accelerating moment release （AMR） usually appears preceding strong earthquakes. In this paper,taking the 1976 Ms7.8 Tang- shan earthquake, the 1998 Ms6.2 Zhangbei earthquake and the 2006 MsS. 1 Wen＇an earth- quake in the northern North China as the target events, we study the AMR phenomena and their characteristics that appeared in circular areas with radii 40 to 120 km centered at the epicenters and within the periods of 4 to 8 years before the three mainshocks. Our re- sult shows that AMR acceleration anormalies appeared in different degrees before both the MsT. 8 Tangshan earthquake and the Ms6.2 Zhangbei earthquake, but did not appear be- fore the MsS. 1 Wen＇an earthquake. Moreover, we find that the radius of 80 km would be an efficient and reasonable spatial scale for scanning and searching AMR acceleration a- nomalies in the study region. Based on the understanding from the three case studies, we further calculate and analyze two regions, the border region among Shanxi, Hebei and In- ner Mongolia, as well as the region of the Capital circle. As a result, areas with AMR ac- celeration anomalies have been identified, and the result may be as a reference in analyzing and determining the future seismic risk in the northern North China.
出处
《地震》
CSCD
北大核心
2014年第1期49-57,共9页
Earthquake
基金
中国地震局地震预测研究所基本科研业务费专项重点项目课题(2010IES010105)
中国地震局监测预报司M7工作专项(2012
2013)联合资助
