3D Deformation Fields Over Southern California From InSAR and GPS

来自 InSAR 和 GPS 的南加州 3D 变形场

• 批准号: 1358573
• 负责人: Rowena Lohman
• 金额: $ 15.07万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1358573&HistoricalAwards=false
• 关键词: 3D; Deformation; Fields; Over; Southern

Non-technical summaryGeodesy -- the study of the shape of the Earth and its changes over time -- helps researchers gain insight into how the Earth's surface deforms in response to faulting, volcanism, hydrologic cycles, landslides, and human activity. Observations of deformation can inform assessments of the hazard associated with individual faults or volcanoes, models of the forces driving plate tectonics, as well as identification of new modes of deformation such as the slow slip events now observed at subduction zones and strike-slip faults worldwide. However, the available data are rarely optimal for the studies that rely on them -- campaign and continuous GPS observations are at isolated points that are usually separated by 10s of km or more, and place less of a constraint on deformation in the vertical direction than in horizontal ones. Space-based geodetic imaging such as Interferometric Synthetic Aperture Radar (InSAR) provides observations over large areas (100s of km) at high spatial resolution (few 10s of meters), but only constrains a near-vertical component of deformation and lacks the temporal resolution of continuous GPS. Tradeoffs between potential models of behavior can usually be greatly reduced when observations of more than one component of the 3D deformation field are available. This project is providing key information about how best to combine these diverse data.Southern California, with its high population density and complex, evolving network of faults, is a region where spatially dense 3-dimensional observations of ground displacements are particularly important. In many cases, the long-term rate and even the fault plane geometry of structures that make up the San Andreas system are poorly understood, as is the manner in which parallel faults accommodate the plate motion over time. The characteristics of the seismic cycle along these faults -- how regular they are, whether earthquakes occur in clusters along one fault followed by hiatuses during which activity shifts to a different structure, etc. -- are necessary inputs into attempts to assess seismic hazard in the region. Technical DescriptionThis project involves assimilation of available GPS and InSAR data into a combined, 3-dimensional map of ground deformation over a study region within Southern California, taking full advantage of the complementary strengths of the two data types. The proposed work includes close examination of the characteristics of seasonal signals, data quality and anthropogenic sources of ground deformation that may contaminate the tectonic signal as well as being of interest in their own right. This project focuses on the transition from the Los Angeles basin through Banning Pass down through the Salton Trough -- an area of interest both because it covers the southern San Andreas fault, but also because it is expected to experience vertical deformation due to both the convergence across many faults in the region and anthropogenic withdrawal of subsurface fluids. The project is developing combined models, and making available to the wider community the underlying data, the models, and the software used to generate those models those models. The project is also supporting the training of a graduate student and formal outreach to female high school students at the CURIE program for STEM development.

非技术总结 - 对地球形状及其随时间变化的研究 - 有助于研究人员深入了解地球的表面如何响应断层，火山循环，水文循环，滑坡和人类活动而变形。变形的观察结果可以告知评估与单个断层或火山相关的危害，驱动板构造的力的模型，以及识别新变形模式，例如现在在俯冲区域观察到的慢速事件和全球俯冲区域的慢速事件。但是，对于依赖于它们的研究，可用的数据很少是最佳的 - 运动和连续的GPS观察在孤立的点上通常被10 km或更高的距离隔开，而在垂直方向上比在水平方向上的变形限制更少。基于空间的大地测量成像，例如干涉合成孔径雷达（INSAR），可在高空间分辨率（几米）（几米）下对大面积（100 km）进行观察，但仅限制了变形的近乎垂直成分，并且缺乏连续GPS的时间分辨率。 当观察到3D变形场的多个组成部分时，通常可以大大降低潜在行为模型之间的权衡。 该项目提供了有关如何最好地结合这些多样化数据的关键信息。加利福尼亚州的人口密度高和复杂，不断发展的故障网络是一个在空间密集的地面位移的3维观测值的区域尤为重要。 在许多情况下，构成圣安德烈亚斯系统的结构的长期速率，甚至是断层平面的几何形状，就像平行断层随着时间的推移适应板运动的方式一样。 沿着这些断层的地震周期的特征 - 它们的规律性，地震是否沿着一个断层发生在簇中发生，然后是在活动中转移到不同的结构等的情况，这是要评估该地区地震危险的必要输入。 技术描述该项目涉及将可用的GP和InsAR数据吸收到南加州的研究区域的组合，3维地面变形图中，充分利用了两种数据类型的互补优势。 拟议的工作包括对季节性信号，数据质量和人为构成的特征的仔细检查，这些特征可能会污染构造信号以及本身感兴趣的特征。 该项目的重点是从洛杉矶盆地通过禁令穿过Salton槽的过渡 - 这是一个有趣的领域，因为它涵盖了南部的San Andreas断层，而且还因为预计它会由于该地区的许多断层和地下液体的拟人化戒断而经历垂直变形。 该项目正在开发合并的模型，并为更广泛的社区提供了基础数据，模型以及用于生成这些模型的软件。 该项目还支持在Curie STEM开发计划中对研究生的培训和对女性高中生的正式宣传。