内蒙古通辽5.3级地震序列特征及发震背景分析

摘要

It is generally known that the Chifeng-Kaiyuan fault functions as the boundary between the North China Block and Northeast Block.On April 22,2013,the Tongliao M 5.3 earthquake occurred in the central segment of the Chifeng-Kaiyuan fault,and thus,it exerted dual influence on the occurrence background in North and Northeast China.This earthquake was determined to be of mainshock-aftershock type based on the results of indicators such as the K value,G-R relationship,energy release rate R E ,and M-T .An analysis of the space-time evolution regularities of moderately strong earthquakes in Northeast China since 1 900,presented in this paper,shows that earthquakes >M 5.0 in Greater Khingan and the Songliao Basin are time-dependent and space-alternating events.Following the Arun-Oroqen border M 5.3 earthquake of 2008,the Tongliao M 5.3 earthquake occurred in the southeastern edge of the Songliao Basin as a moderately strong earthquake.Further comparative studies with past earthquakes in North-east China have shown that this earthquake has both generality and particularity.The space-time evolution regulari-ties of moderate and strong earthquakes in Northeast China,both before and after the 201 1 Japan M 9.0 magnitude earthquake,indicates that compared with other areas of Northeast China,the diamond-shaped area between the Hailaer Basin,Greater Hinggan transition zone,circum-Bohai region,and the Kailu Basin responded most strongly to the 201 1 Japan M 9.0 earthquake.Influenced by the Okhotsk M 8.2 and Japan M 9.0 earthquakes,more than eight M 5. 0 earthquakes occurred in the Songliao Basin in 2013.This article concludes that a new pattern of seismic activity is likely to start in Northeast China in the future.%2013年4月22日在赤峰—开原断裂中段发生了内蒙古通辽5.3级地震,对我国华北和东北地区的地震形势产生双重影响。基于 K 值、G-R 关系、能量释放比例 RE 和 M-T 等指标判定通辽5.3级地震为主震-余震型。根据1900年以来东北地区中强地震时空演化规律分析认为,大兴安岭和松辽盆地5级以上地震具有基于时间相依的空间对跳现象,通辽5.3地震是继2008年6月10日阿荣旗与鄂伦春交界5.2级地震之后,对跳发生于松辽盆地东南边缘的一次中强地震；对比东北地区以往震例分析认为,通辽5.3级地震既具有符合历史统计规律的普遍性,又具有不同于历史统计规律的特殊性。根据2011年3月11日日本东海岸9.0级强震前后东北地区中等以上地震的时空演化特征分析认为,海拉尔盆地及大兴安岭过渡带、环渤海地区至开鲁盆地的“菱形”区域是日本9.0级地震之后我国东部地区响应最为强烈的地区。由于同时受到日本9.0级地震和鄂霍次克海8.2级深震前所未有的双重影响,2013年东北地区的松辽盆地史无前例的发生了8次5级以上中强地震,未来东北地区很可能将重启新的地震活动格局。