利用同震滑坡空间分布样式判识发震断层的研究

Both the co-seismic landslides and identification of seismogenic faults are two difficult issues in earthquake science that receive much attention. While few studies have been made on the correlation between them. The effort in identifying a seismogenic fault using spatial distribution patterns of co-seismic landslides is just in infancy, though it seems promising. On the other hand, the 2013 Lushan earthquake has produced noticeable co-seismic landslides, while no clear co-seismic surface ruptures were found, implying an opportunity to explore this problem. In this application, taking the 2013 Ms 7.0 Lushan, China earthquake as an example, we try to identify the probable seismogenic fault and study the activity of other northeast-striking faults during this event based on spatial distribution patterns of co-seismic landslides, which can provide a new perspective and ideas for the study of the seismogenic fault of the Lushan earthquake. Firstly, we plan to construct a detailed and complete co-seismic landslide inventory map related to the event based on detailed field investigations and visual interpretation of remote sensing images. Then, the spatial distribution pattern of the co-seismic landslides controlled by the seismogenic fault can be derived by excluding other impact factors of the landslides, such as topography and lithology, and the activity of other northeast-striking faults in the earthquake struck area during the earthquake can also be analyzed. Meanwhile, this work also discusses the implication of seismogenic faults on prediction of co-seismic landslides. In addition, the control of the seismogenic fault on co-seismic landslides can be comprehensively analyzed in combination with other earthquake events worldwide, so as to achieve a more convincing identification of the seismogenic fault. This work is expected to bear significance and practical values in research of seismogenic structure of the Lushan earthquake, reconstruction and subsequent disaster prevention and reduction of the affected area, as well as in methodology for identification of seismogenic faults based on co-seismic regional landslides for other earthquake events worldwide.

同震滑坡与发震断层是地震科学颇受关注的两方面。虽然都是当前研究的热点与难点，但是两者综合研究却较少，特别是成因机制联系。利用同震滑坡判识发震断层的研究也仅处于萌芽阶段。2013年芦山地震造成显著滑坡，而地表没有发现明显破裂，致使发震构造研究遇到困难并存在争议。本申请以该地震为例，探索利用同震滑坡判别发震断层，为芦山地震发震机制研究提供新思路。首先基于野外调查与遥感影像解释，构建完整的地震滑坡分布图。然后排除地形、岩性等因素的影响，并考虑震区其它北东向构造的作用，通过模型分析得到受发震断裂控制的滑坡分布样式，为发震断层判别提供依据；进而探讨发震断层模型对地震滑坡预测的意义。最后结合其他震例综合分析发震断层与同震滑坡的机制联系，尝试建立利用同震滑坡判别发震断层的技术流程。本申请预期对芦山地震发震断层认定、震区恢复重建及后续防灾减灾等具有重要的科学与实用价值，也可为其他震例同类研究提供方法指导。

当前，同震滑坡与发震断层是地震科学颇受关注的热点与难点，但是两者综合研究却较少，特别是成因机制联系相关的综合研究。本申请以芦山地震为例，探索利用同震滑坡判别发震断层和发震断层对同震滑坡预测的研究，主要研究包括四个方面。（1）首先基于野外调查与遥感影像解释，建立了当前最详细完整的芦山地震滑坡编录图，结果表明芦山地震共产生了21054处滑坡，滑坡总面积为17.156km2。其中面积大于100m2的滑坡为14483个。该数据库为后续滑坡空间分析、同震滑坡预测、不同震例的滑坡对比分析等的基础。（2）基于芦山地震滑坡的空间分布样式判识出芦山地震发震构造，并分析地震区其他北西向断裂在芦山地震中的活动性，同时结合其他震例综合分析发震断层与同震滑坡的机制联系。通过7个震例的地震滑坡与发震断层的规律研究，发现了一系列两者的新关系，如逆断层型地震比走滑型地震具有更强的地震滑坡触发能力，隐伏逆断层型地震具有与断裂型逆断层地震不同的触发滑坡样式，逆断层发震断层倾角对同震滑坡的控制作用，可以根据同震滑坡推断破裂面的深度变化等。（3）研究发震断层模型对同震滑坡空间预测的意义。排除地形、岩性等因素的影响，通过构建考虑断层的分段性质和断层的发震模式的逻辑回归模型，对比不考虑发震构造模型与考虑发震构造模型得到的芦山地震滑坡预测成果的差异，得到发震模型对地震滑坡预测率的定量影响。（4）为解决当前滑坡危险性统计分析时效性与评估精度不匹配的问题，提出了地震滑坡空间预测的应急救援、中期安置、后期恢复的“三阶段”复合方法。利用Newmark方法和逻辑回归模型探讨了不同阶段内地震滑坡危险性预测的结果，以期为同震滑坡危险性预测提供新的思路。本申请预期对芦山地震发震断层认定、震区恢复重建及后续防灾减灾等具有重要的科学与实用价值，也可为其他震例同类研究提供方法指导。