Collaborative Research: Low-cost imaging and analysis of the August 24, 2014 M6.0 South Napa California earthquake surface rupture (RAPID)

合作研究：2014 年 8 月 24 日 M6.0 南加州纳帕地震地表破裂 (RAPID) 的低成本成像和分析

• 批准号: 1461548
• 负责人: J Ramon Arrowsmith
• 金额: $ 1.63万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1461548&HistoricalAwards=false
• 关键词: Collaborative; Research; Low; cost; imaging

Non-Technical ExplanationMeasurements of the change in shape of Earth's surface following a significant earthquake, including ground offsets caused when faults break all the way to the surface, can be used to understand the physics governing fault behavior, including earthquakes, and the properties of the Earth's crust. These features can be quickly eroded by natural effects and people working to repair damaged structures, roads, and other infrastructure. Rapid documentation of fragile earthquake-generated features is essential for both the scientific characterization of such events as well as for informing emergency response and recovery. New laser scanning (LiDAR) and photogrammetric (Structure from Motion) techniques for generating three-dimensional, "point-cloud" feature reconstructions powerfully augment traditional geological field methods. We are working to develop low-cost Structure-from-Motion technology for post-earthquake capture, measurement, and archiving of surface offsets from the 24 August 2014 Mw 6.0 South Napa earthquake. These data are integrated with post-earthquake airborne laser scanning and compared with pre-earthquake scans to accurately capture the surface rupture and adjacent deformation, and to interpret earthquake processes.Technical DescriptionRapid collection of high-resolution imagery after an earthquake is essential in order to map surface ruptures before onset of degradation or repair, as well as to accurately deconvolve coseismic and post-seismic deformation. The distribution of coseismic slip and the presence and nature of after-slip are both fundamental to understanding the frictional and mechanical properties of faults zones. Fortunately, recent advances in low-cost, aerial topographic imaging and differencing have given geologists the tools to collect and interpret sub-meter resolution imagery at unparalleled resolution and in record time. We are using Structure from Motion (SfM) mapping and multi-temporal airborne Light Detection and Ranging (LiDAR) to map surface offsets and the off-fault, 3-dimensional (3-D) displacement field generated by from the 24 August 2014 Mw 6.0 South Napa earthquake. This is the first ground-rupturing earthquake within the US since the advent of SfM mapping in the early 2010s and also the first with pre-event LiDAR coverage. The study addresses three key scientific questions. (1) What is the accuracy and reproducibility of surface offset measurements? (2) To what extent does early post-seismic deformation bias inferences of coseismic slip at the surface, and at depth? (3) How representative are surface offsets of deeper fault slip and what is the nature of the shallow slip deficit? These questions have implications not only for the mechanics of this fault but also for how such observations are interpreted in other events where such data are lacking. The project will showcase best practice in collecting, interpreting and archiving such data. We will also have strong collaborations with active response activities undertaken with US Geological Survey and California Geological Survey colleagues. These rich datasets will enable us to provide virtual educational experiences in immersive environments.

大地震后，地球表面形状变化的非技术解释计算，包括当断层一路裂开时引起的地面偏移，可用于了解控制断层行为的物理，包括地震，以及地球的壳的特性。 自然效应可以快速侵蚀这些特征，并致力于修复损坏的结构，道路和其他基础设施。 脆弱的地震生成特征的快速记录对于此类事件的科学表征以及为应急和恢复提供了信息至关重要。新的激光扫描（LIDAR）和摄影测量（来自运动的结构）技术，用于生成三维“ Point-Cloud”特征重建，有力地增强了传统的地质场方法。我们正在努力开发低成本的结构，用于从2014年8月24日MW 6.0 South Napa地震开始捕获后捕获，测量和归档地面偏移。这些数据与地震后的激光扫描结合在一起，并与地震前扫描进行比较，以准确捕获表面破裂和邻近的变形，并解释地震过程。技术描述在地震后的高分辨率图像收集到了地震后的高分辨率图像，以绘制出表面破裂的范围，并绘制出范围或修复的范围。后震后变形。 Coseiscic滑动的分布以及后滑动的存在和性质都是理解断层区域的摩擦和机械性能的基础。幸运的是，低成本，空中地形成像和差异的最新进展为地质学家提供了以无与伦比的分辨率和创纪录的时间收集和解释子米分辨率成像的工具。我们正在使用运动（SFM）映射（SFM）映射和多个颞机载的光检测和范围（LIDAR）来映射表面偏移以及由2014年8月24日MW 6.0 South Napa Eartquake产生的偏置，3维（3-D）位移场。这是自2010年代初期SFM映射出现以来，美国境内的第一次地震地震，也是事件前激光雷达覆盖率的第一次地震。该研究解决了三个关键的科学问题。 （1）表面偏移测量值的准确性和可重复性是什么？ （2）在表面上和深度处，coseis震滑的早期后震后变形偏置推断在多大程度上？ （3）较深的断层滑移的表面偏移是如何的，浅层滑移赤字的性质是什么？这些问题不仅对这种故障的机制有影响，而且对在缺乏此类数据的其他事件中如何解释了这种观察。该项目将展示收集，解释和存档此类数据的最佳实践。我们还将与美国地质调查局和加利福尼亚地质调查局进行的积极响应活动进行强有力的合作。这些丰富的数据集将使我们能够在沉浸式环境中提供虚拟教育经验。