Institute of Geology, China Earthquake Administration
School of Earth Science and Resources, China University of Geosciences (Beijing)
China Earthquake Disaster Prevention Center
Hebei Earthquake Agency
National Institute of Natural Hazards, MEMC

活动断层避让是活动断层探测走向减灾应用的最后“1公里”，也是地震链生灾害风险源的阻断技术。地震现场考察和实验研究表明，只要离开活动断层迹线一定的有限距离就能够保证建(构)筑物免遭活动断层同震破裂和错动引起的灾难性毁坏。因此，活动断层的避让工作是活动断层探测和准确定位的最终目标之一。从活动断层避让相关定义和术语出发，系统论述不同类型活动断层地震破裂局部化宽度特征、倾滑断层地表破裂/灾害的上盘效应及其同震破裂和错动对建(构)筑物的剪切和撕裂作用控制了毁坏带空间展布等特征，这些特征构成了活动断层避让理论；在此基础上着重讨论了活动断层避让标准的适用范围、活动断层管制区划定依据和范围，建设场址区避让活动断层所需的定位精度要求，活动断层管制区内一般建(构)筑物避让活动断层距离基本值(D0)，可以作为近于直立走滑断层和倾滑断层下盘避让的最小距离；倾滑断层中倾角约60°正断层上盘的避让距离为避让距离基本值(D0)的2倍左右，而倾角约为30°的逆断层上盘避让距离为避让距离基本值(D0)的3~4倍；特殊建(构)筑物有别于一般建(构)筑物，它们的安全直接影响到社会安定和国家的兴衰，因此，专门给出了分类避让距离，保证这些建(构)筑物在地震期间不会引发严重的次生灾害；最后简明扼要地介绍了国内外活动断层避让的相关法律法规和避让实例。活动断层避让作为一种科学有效的地震灾害阻断技术，不仅可以有效地解决建(构)筑物的抗断问题：如何避让？避让多少？还可为保障国家经济社会可持续发展和“一带一路”基础设施建设的地震安全提供创新性技术支撑。

Determining setbacks from active faults is the “last 1 km” from active fault surveys to their application to seismic disaster mitigation. It is also a technique for blocking the risk sources of earthquake-induced chains of geologic hazards. Field investigations and experimental studies have demonstrated that buildings and structures can be free from catastrophic destruction caused by coseismic ruptures and offset of active faults provided they are kept at a certain finite distance from the active fault traces. Therefore, determining setbacks from active faults serves as an ultimate goal of the surveys and precise localization of active faults. Based on the definitions and terminologies related to setbacks from active faults, this study systematically analyzes the width of earthquake rupture localization of various active faults, the hanging-wall effects of surface ruptures/disasters induced by dip-slip faults, and the shearing and tearing of buildings and structures caused by the coseismic ruptures and offset of active faults, which jointly shape the spatial distribution of destruction zones. These characteristics constitute the theory of setbacks from active faults. Accordingly, this study highlights the application scopes of standards for setbacks from active faults, the bases and ranges for delineating the regulatory zones of active faults, the positioning accuracy of setbacks from active faults required for construction sites, and the basic setback distance (D0) for general buildings and structures within the regulatory zones around active faults. This value can be used as the minimum distance for setbacks from the foot walls of nearly vertical strike-slip faults and dip-slip faults. It is recommended that the setback distance from the hanging walls of normal faults with dip angles of about 60° and reverse faults with dip angles of about 30° should be approximately twice and 3 to 4 times D0, respectively. For particular buildings and structures, different from general ones, their safety directly influences social stability and national prosperity. Therefore, this study presents classified setback distances specific to these buildings and structures to ensure that they will not induce serious secondary disasters during earthquakes. Finally, this study briefly introduces domestic and international laws/regulations concerning setbacks from active faults, along with illustrative examples. As a scientific and effective technique for blocking earthquake-induced geologic hazards, determining setbacks for active faults can effectively determine setback means and distance for the anti-rupture of buildings and structures. Furthermore, this technology provides innovative technical support for ensuring the seismic safety of the sustainable economic and social development of China and the infrastructure construction of the “Belt and Road” Initiative proposed by the country.

国家自然科学基金项目(41941016)；国家重点研发计划课题(2021YFB2301401)

魏雷鸣，徐锡伟，李峰，等. 活动断层避让距离确定的理论基础与应用实例[J]. 煤田地质与勘探，2023，51(12)：69−82.

WEI Leiming，XU Xiwei，Li Feng，et al. Theory and application of setback distance from active faults[J]. Coal Geology & Exploration，2023，51(12)：69−82.