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Title:: Preliminary Study on Characteristic of Paleoearthquakes on the Lancang Fault in the Southwestern Area of Yunnan

作者:: 刘兴旺¹; 2; 3; 袁道阳¹; 何文贵¹; 2; 张波¹; 2; 方良好⁴; (1.中国地震局兰州地震研究所,甘肃兰州730000; 2.中国地震局地震预测研究所兰州科技创新基地,甘肃兰州730000; 3.兰州大学西部环境教育部重点实验室,甘肃兰州730000; 4.安徽省地震局,安徽合肥 230031)

Author(s):: LIU Xingwang¹; 2; 3; YUAN Daoyang¹; HE Wengui¹; 2; ZHANG Bo¹; 2; FANG Lianghao⁴; (1.Lanzhou Institute of Seismology,CEA,Lanzhou 730000,Gansu,China)(2.Lanzhou Base of Institute of Earthquake Science,CEA,Lanzhou 730000,Gansu,China)(3.Key Laboratory of western China's Environmental System with the ministry of Education,Lanzhou University,Lanzhou 73000,Gansu,China)(4.Earthquake Administration of Anhui Province,Hefei 230031,Anhui,China)

Keywords:: Lancang Fault; paleoearthquake; earthquake recurrence interval; ¹⁴C dating

摘要:: 通过卫星影像解译、野外实地调查和地质填图,对滇西南地区的澜沧断裂的最新活动性开展了翔实的调查,重点对该断裂的古地震特征进行了分析,通过中南段3个探槽剖面的详细分析和样品年代测试,对其存在的古地震事件进行了判定,初步确定了6次古地震事件的发生年代,分别为距今约3 700 a、2 300～2 500 a、1 200～2 000 a、900～1 200 a、500～600 a和20 a。古地震具有周期复发的特征,其复发间隔为500～600 a。

Abstract:: According to satellite image interpretation,field investigation and geological mapping,we investigated the latest activity of Lancang Fault which is located in the southwestern area of Yunnan.On the basis of characteristic of the latest activity of Lancang Fault,we focus on analyzing the characteristic of the paleoearthquakes on the fault.After analyzing the three trench profile in detail on the middle south segment of the fault and the testing of the sample dating,we primarily determined that the occurrence time of six paleoearthquakes was about 3700 a,2 300～2 500 a,900～1 200 a,1 200～2 000 a,500～600 a,and 20 a ago respectively.The paleoearthquakes had the characteristics of periodic recurrence,and the recurrence interval is 500～600 a.