正谊关断裂带的新活动与古地震研究

RESEARCH ON NEW ACTIVITY AND PALEOEARTHQUAKES OF ZHENGYIGUAN FAULT BELT

摘要:

正谊关断裂横贯贺兰山北部山区,为一长期活动的区域性大断裂带。本文根据大比例尺航卫片解译,野外实际调查资料和¹⁴C年代数据,讨论了该断裂带的平面展布、第四纪以来断裂的运动方式,活动强度、最新活动时代及古地震等问题。该断裂带的正谊关断层段新活动强烈,第四纪以来呈明显的左旋走滑活动。断错地貌显示,其最大一组水平错距为1800-2000米,最小一组错距为10-20米。在毛呼都格音沟及葡萄泉子沟发现两处古地震遗迹,估计该两次古地震事件发生在距今约6000年左右。

Abstract:

Zhengyiguan fault belt crosses the northern area of Helanshan mountain,and it is a regionaly great fracture with a long-term activity.Based on the interpretation of air and satellite photoes at a largescale,field investigation data and ¹⁴C dating,this paper discusses and analyses the plane distribution range,active way and active intensity since Quaternary,the latest active time and paleoearthquakes etc.of this fault belt.The newest activity of Zhengyiguan fault belt is intensive and obvious.Since Quaternary,the fault shows apparent left-lateral slip.The faulted geomorphology shows the maximum distance of horizontal dislocation is 18 00-2000m,and the minimum is 10-20 m.There exist two paleoearthquake traces at Maohudugeyinggou and Putaoqnanzizou,it is estimated that the paleoearthquakes occurred about 6000 years ago.