3D Deformation Fields Over Southern California From InSAR and GPS

大地测量学--研究地球的形状及其随时间的变化--帮助研究人员深入了解地球表面如何因断层、火山活动、水文循环、山体滑坡和人类活动而变形。对变形的观测可以为评估与个别断层或火山有关的危险、驱动板块构造的力的模型以及识别新的变形模式提供信息，例如现在在世界各地的俯冲带和走滑断层观察到的缓慢滑动事件。然而，现有的数据很少是最佳的研究，依靠他们-运动和连续的全球定位系统观测是在孤立的点，通常是由10公里或更多的分离，并放置在垂直方向的变形比在水平方向的约束较少。天基大地测量成像，如干涉合成孔径雷达（干涉合成孔径雷达），以高空间分辨率（几十米）对大面积（几百公里）进行观测，但仅限制变形的近垂直分量，缺乏连续全球定位系统的时间分辨率。 当3D变形场的一个以上分量的观测可用时，通常可以大大减少潜在行为模型之间的权衡。 该项目提供了关于如何最好地结合联合收割机这些不同数据的关键信息。南加州人口密度高，断层网络复杂，不断发展，是一个空间密集的三维地面位移观测特别重要的地区。 在许多情况下，人们对组成圣安德烈亚斯系统的构造的长期速率甚至断层面几何形状都知之甚少，就像平行断层随时间推移适应板块运动的方式一样。 沿这些断层沿着的地震周期的特点-它们有多规则，地震是否沿沿着一个断层成簇发生，然后是活动转移到另一个结构的间歇期，等等-是评估该区域地震危险的必要投入。 技术说明本项目涉及将现有的GPS和干涉合成孔径雷达数据同化为一幅综合的三维地形图，该地形图覆盖南加州的一个研究区域，充分利用了两种数据类型的互补优势。 拟议的工作包括仔细检查季节性信号的特征、数据质量和可能污染构造信号的地面变形的人为来源，以及它们本身的利益。 该项目的重点是从洛杉矶盆地通过班宁山口向下通过索尔顿海槽的过渡-这是一个令人感兴趣的区域，因为它覆盖了南圣安德烈亚斯断层，而且由于该区域许多断层的会聚和地下流体的人为抽取，预计它将经历垂直变形。 该项目正在开发综合模型，并向更广泛的社区提供基本数据、模型和用于生成这些模型的软件。 该项目还支持培训一名研究生，并在Curie科学、技术、工程和数学发展方案中向女高中生开展正式外联活动。

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.