EAR/IF: Prototype Investigations into Integrated GPS/Seismic Networks for Improved Finite Fault Slip Modeling and Earthquake Characterization

最近发生在苏门答腊岛、智利和日本的大地震和随之而来的海啸表明，需要精确的地面位移，以充分表征与这些巨大而复杂的破裂相关的大振幅和宽动态范围。我们对这些事件建模的能力，无论是实时的还是事后的，都受到地震和大地测量网络弱点的限制。大地测量仪器提供静态部分以及粗略的动态运动，但远不如地震仪器精确，特别是在垂直方向上。反过来，地震仪器提供异常敏感的动态运动，但由于仪器倾斜等污染，通常难以恢复无偏的近场静态偏移和低频运动。这个为期三年的项目展示了一种研究大地震过程及其危害的新范式。通过整合斯克里普斯海洋研究所开发的大地测量和地震测量仪器，将实现跨越地震运动全谱的精确三维地震大地测量波形（宽带位移和速度）。主要的科学目标是通过观测水平的大地测量和地震数据的最佳组合来改进有限断层滑动反演，并研究使用所得数据进行全波形反演的适当方法。联安援助团的工程师正在沿着南圣安德烈亚斯断层系统的现有实时板块边界观测站建立一个综合GPS/地震台站试验台，作为沿着北美西部板块边缘进一步扩展的一个原型。这些台站正在升级为低成本的MEMS加速度计和一个大地测量模块，该模块将同步GPS和加速度计数据，并估计地震大地测量位移和速度。该项目正在安装和测试对现有GPS监测站的地震升级，以改进对大地震和随之而来的海啸的反应、建模和理解，例如最近在苏门答腊、智利和日本发生的地震。该项目的广泛影响在科学价值、工程基础设施、民用和经济影响方面都是显著的，并且在很大程度上与增强的GPS/地震监测的实时性和能力有关。新的观测结果直接有助于自然灾害研究和地震、火山和海啸的早期预警系统，包括短期天气预报和相关洪水灾害在内的大气研究，以及大型结构（如桥梁、建筑物、水坝）的地震工程研究。最终目标是挽救生命，并尽量减少对重要基础设施的破坏。新的观测结果也有助于需要精确实时定位的民用应用（例如，测量、地理信息系统、农业），从而促进经济刺激。最后，该项目支持协作和跨学科研究，教育技术先进的研究生，加强多样性以支持劳动力发展，并通过参与具有直接社会影响的新型数据集，在各个层面上改进课程。

Recent great earthquakes and ensuing tsunamis in Sumatra, Chile and Japan have demonstrated the need for accurate ground displacements that fully characterize the great amplitudes and broad dynamic range associated with these vast, complex ruptures. Our ability to model these events, whether in real-time or after the fact, is limited by the weaknesses of both seismic and geodetic networks. Geodetic instruments provide the static component as well as coarse dynamic motions but are much less precise than seismic instruments, especially in the vertical direction. Seismic instruments, in turn, provide exceptionally-sensitive dynamic motions but typically have difficulty recovering unbiased near-field static offsets and low-frequency motions because of contamination, for example, from instrument tilt. This three-year project is demonstrating a new paradigm for studying the processes of large earthquakes and the hazards they pose. Accurate three-dimensional seismogeodetic waveforms (broadband displacements and velocities) that span the full spectrum of seismic motion will be achieved through integration of geodetic and seismic measurements instrumentation developed at Scripps Institution of Oceanography. The main science objectives are to improve finite-fault slip inversions through the optimal combination of geodetic and seismic data at the observational level and to investigate appropriate methodologies to perform full waveform inversions using the resulting data. With UNAVCO engineers, a test bed of integrated GPS/seismic stations is being established at existing real-time Plate Boundary Observatory stations along the southern San Andreas fault system as a prototype for further expansion along the Western North America plate margin. The stations are being upgraded with low-cost MEMS accelerometers and a Geodetic Module that will synchronize the GPS and accelerometer data and estimate seismogeodetic displacements and velocities.The project is installing and testing seismic upgrades to existing GPS monitoring stations for improved response to and modeling and understanding of large earthquakes and ensuing tsunamis, such as recent ones in Sumatra, Chile and Japan. The broader impacts of this project are significant in terms of scientific value, engineering infrastructure, civilian use, and economic impact, and are related for the most part to the real-time nature and capabilities of enhanced GPS/seismic monitoring. The new observations contribute directly to natural hazards research and early warning systems for earthquakes, volcanoes and tsunamis, to atmospheric research including short-term weather forecasting and related flooding hazards, and to earthquake engineering research for large structures (e.g., bridges, buildings, dams). The ultimate goal is to save lives and minimize damage to essential infrastructure. The new observations also contribute to civilian applications requiring precise real-time positioning (e.g., surveying, geographic information systems, agriculture) and hence to economic stimulus. Finally, the project supports collaborative and interdisciplinary research, education of technologically sophisticated graduate students, strengthening of diversity in support of workforce development, and enhancement of curricula at a variety of levels through engagement new types of data sets that have direct societal impact.