断裂性质与滑坡分布的关系——以汶川地震中的大型滑坡为例  

STUDY ON THE FAULT MECHANICS INFLUENCES ON THE LANDSLIDES DISTRIBUTION: A CASE STUDY FROM THE WENCHUAN EARTHQUAKE

作　　者：陈晓利[1] 惠红军[2] 赵永红[2] 

机构地区：[1]中国地震局地质研究所,活动构造与火山重点实验室,北京100029 [2]北京大学地球与空间科学学院,造山带与地壳演化教育部重点实验室,北京100871

出　　处：《地震地质》2014年第2期358-367,共10页Seismology and Geology

基　　金：中国地震局地震行业专项"地震安全性评价分类;关键技术指标确定及国家标准修订研究(201408002)"资助

摘　　要：越来越多的地震滑坡相对于地震断层的不对称分布震例让人们意识到断层上盘效应的存在。然而,目前有关断裂运动方式与滑坡空间分布关系的研究还不够充分和深入。在收集大量地震滑坡震例资料并获得其分布规律的基础上,建立了一个简化的断层模型,以地震波在地表与断层面之间反射传播特性为基础,探讨断层倾角改变对地表地震动强度的影响。进而,以汶川地震触发的大型滑坡为例,研究了断层的几何特征和运动方式对诱发滑坡空间分布的影响。结果表明,断层的倾角对滑坡空间分布范围具有控制作用,随着倾角的增加,垂直断层走向的滑坡分布范围逐渐减小;并且,大型滑坡的初始坡面受到断裂运动方向的影响,与断裂运动方向一致的坡面更容易发生滑坡。所获结果不仅有助于提高区域性地震滑坡危险区域的预测精度,而且对认识大型滑坡的滑动机制、主控因素以及可能的滑动规模、滑距等也起到促进作用。通过对滑坡崩塌的认识来辅助提高对地质构造、地震断层等的认识,应是地震诱发滑坡崩塌研究的新的意义所在。More and more earthquake-triggered landslides show the hanging wall effects on the spatial distribution, however, the effects of seismic fault mechanics on landslides development are not clear at present time. Based on a simplified fault model, the knowledge of seismic waves reflecting between the ground surface and the fault plane is applied to explain the reasons why landslides are asymmetrically distributed on the hanging wall side during earthquakes caused by thrust faults. Moreover, this paper discusses the relationship between fault movement directions and the initial slope aspects based on the data of large landslides which occurred during the Wenchuan earthquake. This study shows that fault dip angle can affect landslides distribution, namely with the increasing of fault dip angle, the width of the region subjected to the landslides on the hanging wall side decreases. Also, the slopes whose aspects are in the similar directions as the initial movement direction of seismic fault are prone to failure. The knowledge obtained in this study will help to improve the accuracy in regional earthquake-triggered landslide susceptibility assessment and promote the research on the large landslides mechanism, major influencing factors as well as the possible landslide scales.

关 键 词：地震滑坡 断层类型 断裂倾角 坡向 运动方向 

分 类 号：P315.9[天文地球—地震学]