金州断裂盖州北—鞍山段古地震破裂的新证据  

NEW EVIDENCE OF THE PALEOEARTHQUAKE RUPTURE IN THE NORTH GAIZHOU-ANSHAN SEGMENT OF THE JINZHOU FAULT

作　　者：李安[1,2] 万波 王晓先[2] 计昊旻 索锐 LI An;WAN Bo;WANG Xiao-xian;JI Hao-min;SUO Rui(State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China;National Institute of Natural Hazards,Ministry of Emergency Management of China,Beijing 100085,China;Liaoning Earthquake Agency,Shenyang 110031,China)

机构地区：[1]中国地震局地质研究所,地震动力学国家重点实验室,北京100029 [2]应急管理部国家自然灾害防治研究院,北京100085 [3]辽宁省地震局,沈阳110031

出　　处：《地震地质》2023年第1期111-126,共16页Seismology and Geology

基　　金：中国地震局地质研究所基本科研业务专项(ZDJ2019-16);中国地震局城市活断层探测与地震危险性评价项目(152007000000170013)共同资助;郯庐断裂带三维地震构造分段模型与地震预测研究专项(TYZ20160110)。

摘　　要：1975年海城MS7.3地震是中国第1次成功预报的7级以上破坏型地震,避免了大量人员和财产损失。但在地震后的调查中并没有发现较为连续的地表破裂带,只在零星地点发现了一些地表裂缝和喷砂冒水现象。该地震的等震线表现出较为明显的共轭特征,因此研究者对于海城地震的发震断层一直存在一定争议。文中对与海城河断裂共轭相交的金州断裂盖州北—鞍山段进行了遥感影像解译、微地貌测量和古地震探槽开挖等工作,发现金州断裂自大石桥市沿NE向至鞍山市南,在盆山过渡带的晚更新世和全新世地貌面上存在较为明显的沿NE向展布的断层陡坎。由于人类活动,断层陡坎展布不连续。断层陡坎的高度多为1~2m,最大可达3m;在海城市南葫芦峪村开挖的古地震探槽揭露出盖州北—鞍山段具有宽约20m的基岩破碎带,晚更新世晚期—全新世以来(距今(37.6±2.2)ka)至少发生过2次古地震事件。较新的一次地震发生于全新世(距今(11.7±0.8)ka以后,很可能为距今400~500a)。由于全新世地层太薄所限,无法识别出更多全新世古地震,但可以判断金州断裂盖州北—鞍山段为晚更新世晚期—全新世活动断裂。The Haicheng MS7.3 earthquake is the first successfully predicted earthquake in China,which saved a large number of lives and avoided property losses.However,the investigation after the earthquake did not find a continuous surface rupture zone,and only some ground fissures and sandblasting were found in the epicenter area.The isoseismal line of this earthquake shows obvious conjugate characteristics.Which fault is the seismogenic structure of the Haicheng earthquake has always been controversial.According to the focal mechanism and distribution of ground fissures,some scholars suggested the seismic structure is the Haicheng River Fault with a strike of NWW.However,other scholars suggested the Jinzhou Fault has a larger scale and controls the geomorphic boundary.Jinzhou Fault is also a major seismic structure distributed in the west of Liaodong Peninsula,with a strike of NE—NNE and a length of 280km.The north Gaizhou-Anshan segment of the Jinzhou Fault is conjugated with the Haicheng River Fault.Both of them are likely to be the seismogenic structure of the Haicheng earthquake,or both ruptured in the Haicheng earthquake.Based on remote sensing image interpretations,four sites of the fault scarps,including the Yujiagou,Houwudao,Dongjiagou,and Tashan sites,were distinguished and verified in situ.And using micro geomorphology measurement and paleoseismic trench excavation in the Huluyu site of the north Gaizhou-Anshan segment of the Jinzhou Fault which is conjugated with the Haicheng River Fault,this paper obtains the following understandings:The Jinzhou Fault extends from the northeast of the Dashiqiao City to the south of the Anshan City.There are prominent NE-trending fault scarps,which were formed in the late Pleistocene and Holocene,on geomorphic surfaces of the basin mountain transition zone.Due to farming and building,fault scarps are not preserved well,and the distribution of the fault scarp is discontinuous.The height of fault scarps is mostly 1~2m,up to 3m at most.The paleoseismic trench was excavated in

关 键 词：金州断裂 古地震 断层陡坎 海城地震 

分 类 号：P315.2[天文地球—地震学]