Collaborative Research: 3-D Near-field Coseismic Deformation from Differential LiDAR with Application to the El Mayor-Cucapah Earthquake

断层带激光雷达扫描最强大的应用之一是作为之前的图像，与未来地表破裂地震后获得的调查进行比较。然后，每一个位移的功能作为一个大地测量标记，从超高分辨率地图的表面位移场可以构建。这样一个详细的位移场显示了断层及其包含的岩石体积如何共同作用，以适应连续地震的变形和地质结构的发展。这为地震破裂如何连接断层以产生更大，更具破坏性的事件提供了新的理解，并阐明了改进长期变形率和地震危险性估计所需的变形的隐蔽，分布式组件。通过NSF EarthScope计划和NSF国际科学与工程办公室的美洲计划获得的这笔赠款支持开发全三维方法，以解开断层带连续机载LiDAR扫描的变形。该项目的重点是2010年4月4日墨西哥北方下加利福尼亚El Mayor-Cucapah（EMC）地震破裂前后的机载激光雷达扫描。该项目的目标是解决使用这一数据集的三个挑战：（1）对震前数据进行再处理，以减少扫描伪影并提高准确性;（2）开发方法，从分辨率相差悬殊的点云数据中进行严格的高分辨率位移测量（9 - 18 pts/m ~ 2，而震前为0.013 pts/m ~ 2）;（3）本次地震断层带变形的初步三维力学模拟。满足这些挑战将进步的断层带变形的知识，从这次地震中获得，以及先进的技术，分析下一次地震捕获的差分激光雷达-很可能沿着的一个众多的活动断层成像的Earthscope facility. Coesteismatic地表破裂的一部分，是一个重要的，可访问的地震滑动记录，和史前地震活动的主要记录。差分LiDAR的近场形变测量可以改变我们对同震地表破裂如何产生和分布在断层带内的理解。要获得的新知识包括理解断层滑动与近场分布变形的机械耦合，量化断层滑动的分布分量，否则难以测量，并预测可能损坏建筑物和关键基础设施的断层带周围高应变的类型，范围和幅度。为这个项目开发的技术也将被证明对其他应用有价值，如地貌学，土木工程和机器人技术。这项研究汇集了来自美国五个国家的专业知识-这些研究小组是差分机载激光雷达研究的领导者：加州大学戴维斯分校、亚利桑那州立大学、加州大学圣地亚哥分校、休斯顿大学和加州理工学院/美国地质勘探局。该项目还扩大了EMC地震后形成的国际合作，让下加利福尼亚CICESE的研究人员和学生参与开发和部署新的差分LiDAR算法和开源LiDAR可视化软件。

One of the most powerful applications of fault-zone LiDAR scans is to serve as the before image for comparison with a survey acquired after a future surface-rupturing earthquake. Then, every displaced feature acts as a geodetic marker from which an ultra-high resolution map of the surface displacement field may be constructed. Such a detailed displacement field shows how faults and their containing rock volume act together to accommodate deformation and grow geologic structures over successive earthquakes. This provides new understanding of how earthquake ruptures connect faults to generate larger, more destructive events, and illuminates cryptic, distributed components of deformation needed for improving estimates of long-term deformation rates and seismic hazard. This grant through the NSF EarthScope Program and the Americas Program of the NSF Office of International Science and Engineering supports the development of fully 3-dimensional approaches to unraveling deformation from successive airborne LiDAR scans of a fault zone. The focus of the project is the before and after airborne lidar scans of the April 4, 2010 El Mayor-Cucapah (EMC) earthquake rupture in northern Baja California, Mexco. The project objectives address three challenges in working with this data set: (1) reprocessing of the pre-earthquake data to reduce scanning artifacts and improve accuracy; (2) development of methods for rigorous, high-resolution displacement measures from point-cloud data of vastly different resolutions (9 to 18 pts/m2 post-earthquake compared with 0.013 pts/m2 pre-earthquake); (3) preliminary 3-D mechanical modeling of fault-zone deformation from this event. Meeting these challenges will advances knowledge of fault-zone deformation gained from this earthquake, as well as advance techniques for analysis of the next earthquake captured by differential LiDAR -- quite possibly along one of the numerous active faults imaged as part of the Earthscope facility.Coseismic surface rupture is an important, accessible record of earthquake slip, and the primary record of prehistoric seismicity. Near-field deformation measurements from differential LiDAR can transform our understanding of how coseismic surface ruptures are produced and distributed within fault zones. New knowledge to be gained includes understanding the mechanical coupling of fault slip to near-field distributed deformation, quantifying distributed components of fault slip otherwise difficult to measure, and predicting the style, extent, and magnitude of high strains around fault zones that could damage buildings and critical infrastructure. The techniques developed for this project will also prove valuable for other applications, such as in geomorphology, civil engineering, and robotics. This research brings together the expertise from five U.S.-based research groups that are leaders in the study of differential airborne LiDAR: UC Davis, Arizona State, UC San Diego, University of Houston, and Caltech / USGS. This project also broadens international collaborations formed following the EMC earthquake by involving researchers and students from CICESE, Baja California, in the development and deployment of new differential LiDAR algorithms and the open-source LiDAR-visualization software.