• 首页关于本刊投稿须知期刊订阅编委会期刊合作查询检索English

查看全文   查看HTML全文 下载PDF阅读器  

  方良好,袁道阳,邵延秀,王爱国,何文贵,刘方斌.滇西南地区黑河断裂西段古地震形变带特征[J].震灾防御技术,2015,10(2):271-280, DOI:10.11899/zzfy20150207.

滇西南地区黑河断裂西段古地震形变带特征
摘要:    位于滇西南地区的黑河断裂从西向东可分为沧源-木戛、木戛-南代和南代-勐往3条次级断裂段,长约168km,性质以右旋走滑为主,兼具倾滑分量。通过较详细的野外追踪考察,发现该断裂西段即沧源-木戛段存在从雪林大寨以西至木戛长12km以上、北西向断续展布的古地震形变带,主要表现为基岩裂缝、田埂和山坡等右旋扭动显示的右旋断错,断错量0.5—2m,同时还形成了高0.5—1m的断层陡坎。陡坎的垂直位错是断层倾滑运动分量引起的,而地形效应和重力作用也有一定影响。从这些地表形变带的断错地层、陡坎形态等分析,认为是同1次地震活动的结果,经调查访问其不是1988年澜沧7.6级地震的地表形变带,而是时代相对较新的未知年代的古地震形变带。经探槽开挖和样品年代测试,确认其时间介于(1400±30)a.B.P.—(1714±49)a.B.P.之间。根据走滑型地震的震级与同震位错的经验统计关系,估算该次地震的矩震级≥7级,这与该断裂中段即木戛-南代段发生的1988年澜沧MS7.6级地震相当。
作者单位
方良好 中国地震局兰州地震研究所兰州730000 安徽省地震局合肥230031 
袁道阳 中国地震局兰州地震研究所兰州730000 兰州地球物理国家野外科学观测研究站兰州730000 
邵延秀 中国地震局兰州地震研究所兰州730000 兰州地球物理国家野外科学观测研究站兰州730000 
王爱国 中国地震局兰州地震研究所兰州730000 兰州地球物理国家野外科学观测研究站兰州730000 
何文贵 中国地震局兰州地震研究所兰州730000 兰州地球物理国家野外科学观测研究站兰州730000 
刘方斌 中国地震局兰州地震研究所兰州730000 
关  键  词:滇西南地区  黑河断裂西段  古地震形变带  断层陡坎  地震震级
DOI:10.11899/zzfy20150207
基金项目:公益性地震行业科研专项“中国地震活断层探察——南北地震带中南段”(201108001)资助
收稿日期:2014-08-25
作者简介:方良好,男,生于1984年。2013年获中国地震局兰州地震研究所构造地质学硕士学位,现在安徽省地震局工作。主要研究方向为活动构造及其应用研究。E-mail: logfang@163.com
通讯作者:袁道阳,男,生于1965年。博士,研究员。主要从事活动构造研究。E-mail: daoyangy@163.com.
The Features of Earthquake Surface Rupture Zone on the Western Segment of Heihe Fault in Southwestern Yunnan Province
Abstract:      Through field investigation on the western segment of the Heihe Fault, i.e., Cangyuan - Mujia (F1-1), we found a 12km-long seismic surface rupture zone trending NW along the west of Xuelindazhai village to Mujia village. This surface rupture zone consists of a series of dextral dislocation of balks, hillside and bedrock fissure. The fault rupture zone offset the balks and the uplift is 0.5-1m. The dextral dislocation of balks is 0.5-2m. The vertical dislocation part is partially due to fault scarp dip-slip component combining with the terrain and gravity effect. The shape and size of this surface rupture is similar to that of the remaining deformation zone of MS7.6 event in Lancang,1988. Based on the empirical relationship, MW=7.04+lgAD between moment magnitude of strike-slip earthquake MW, and coseismic average dislocation AD(m), we estimate the magnitude of the earthquake is greater than 7. It is similar with MS7.6 event in Lancang, 1988, in the middle of the Heihe fault, i.e., Mujia - Mengwang (F1-2). Their coseismic dextral displacements are about equal. In this paper, the palaeo-earthquake events on the western segment of Heihe fault are studied. Combining the trench profile, fault profiles and profiles characteristics, we have a preliminary understanding with characteristics of late Quaternary tectonic activity and palaeo-earthquake events of this segment. We conclude that two earthquakes had occurred since (2880±25)a.B.P. on the western segment of Heihe Fault, the latest of earthquake events is between(1400±30)a.B.P. and(1714±49)a.B.P..
Keywords:  Southwestern part of Yunnan province  The western segment of Heihe fault  Paleoearthquake  Fault scarp  Earthquake magnitude
关闭