Collaborative Research: Strain Rate and Moment Accumulation Rate along the San Andreas Fault System from InSAR and GPS

合作研究：InSAR 和 GPS 沿圣安地列斯断层系统的应变率和力矩累积率

• 批准号: 1147435
• 负责人: David Sandwell
• 金额: $ 22万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-15 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1147435&HistoricalAwards=false
• 关键词: Collaborative; Research; Strain; Rate; Moment

The San Andreas Fault System (SAFS) is a natural laboratory for investigating the physics of the earthquake cycle along a major continental transform boundary. Two of the key parameters that can be used for seismic hazard assessment are seismic moment accumulation rate and strain accumulation rate. The GPS component of the Plate Boundary Observatory (PBO) provides accurate vector velocities ( 1 mm/yr accuracy) at a spacing of 10 to 20 km along the SAFS. However, the velocity gradient (strain rate) varies most rapidly within 20 km of the major faults, so strain rate is not well resolved by the GPS data alone. Radar interferometry (InSAR) provides deformation maps at 100 m spatial resolution, although factors such as temporal decorrelation and atmospheric path errors have made it difficult to achieve this full resolution with sufficient precision to improve upon the GPS measurements. The L-band data provided by the ALOS satellite (JAXA) retains phase coherence over longer time intervals than the prior C-band missions. This improvement, combined with stacking techniques to reduce atmospheric errors, now makes it possible to image the entire SAFS using InSAR with unprecedented spatial coverage and resolution.The primary focus of this research is to construct high spatial resolution vector surface deformation measurements by combining the high accuracy point measurements provided by PBO GPS data with the high spatial resolution InSAR measurements available through WInSAR from foreign and domestic SAR missions. The research has four main objectives:- Resolve secular plate boundary deformation using new GPS and InSAR measurements provided by EarthScope (PBO and WInSAR). This involves the development of community software to preprocess the new data streams to be provided by the ALOS-2 and Sentinel-1 InSAR satellites (2013 launch);- Use an integrated GPS-4D model-InSAR technique to better constrain fault slip rates and determine the depth of the locked/creeping transition on active faults of the SAFS;- Generate high-resolution estimates of strain rate and seismic moment rate along major faults of the SAFS; and- Explore methods for isolating non-tectonic deformation contributions common in both InSAR and GPS data.Non-technical summaryIs California prepared for the next big earthquake? Estimates of earthquake potential along major faults, such as the San Andreas Fault System (SAFS), are used for developing scenario earthquakes, for setting regional building codes, and for setting earthquake insurance rates. While the timing of a major earthquake cannot be accurately predicted, the moment magnitude can be accurately estimated from geodetic measurements of present-day crustal deformation. The current array of 700 continuously operating GPS stations in western North America does not completely resolve the crustal deformation gradients (strain) along the major faults because the average station spacing is too large. This research is refining the crustal deformation measurements by computing and modeling the synthetic aperture radar data (SAR) archived at the Western North America InSAR consortium (WInSAR) and the Alaska Satellite Facility. This involves the generation and archive of large-scale (1000 km scale) crustal deformation grids at 0.5 km spatial resolution in a near-automatic fashion. Funding from this grant is supporting two Ph.D. students at SIO and UTEP (a Hispanic Serving Institute) and is being used for further development of undergraduate and graduate courses. This funding is also being used to develop a ?How InSAR Works? module for use in IRISʼs Active Earth interactive kiosks on display around the country. In addition, funding is being used to move the GMTSAR software into the GMT distribution system where it is available to 15,000 users worldwide. We are distributing all high-resolution vector deformation data and maps to the scientific community and archive the results at UNAVCO.

San Andreas断层系统（SAFS）是一个自然实验室，用于研究沿主要大陆变换边界的地震周期的物理。可用于地震危害评估的两个关键参数是地震矩积累率和应变累积率。板边界观测站（PBO）的GPS分量在沿SAFS沿10到20 km的间距下提供准确的矢量速度（1 mm/yr精度）。但是，速度梯度（应变速率）在主要断层20公里内变化最大，因此仅GPS数据就无法很好地解决应变率。雷达干涉法（INSAR）在100 m空间分辨率下提供了变形图，尽管时间去相关和大气路径误差等因素使得难以实现这一完整分辨率，并具有足够的精确度以改进GPS测量。与先前的C波段任务相比，ALOS卫星（JAXA）提供的L波段数据在更长的时间间隔内保持相位连贯性。 This improvement, combined with stacking techniques to reduce atmospheric errors, now makes it possible to image the entire SAFS using InSAR with unprecedented spatial coverage and resolution.The primary focus of this research is to construct high spatial resolution vector surface deformation measurements by combining the high accuracy point measurements provided by PBO GPS data with the high spatial resolution InSAR measurements available through WInSAR from foreign and domestic SAR missions.该研究具有四个主要目标： - 使用新的GPS和EarthScope（PBO和Winsar）提供的新GP和INSRAR测量结果解决世俗板块边界变形。这涉及开发社区软件，以预处理新数据流由ALOS-2和Sentinel-1 Insar卫星提供（2013年发布）； - - 使用集成的GPS-4D Model-Insar技术来更好地限制故障滑移速率，并确定锁定/蠕变的锁定/蠕变过渡的safs saf; saf saf的高度率和较高率的速度率的锁定率和蠕变的速度均;和探索方法用于隔离INSAR和GPS数据中常见的非构造变​​形贡献的方法。加利福尼亚州为下一次大地震做准备的非技术摘要吗？估计沿重大断层的地震潜力的估计，例如圣安德烈亚斯断层系统（SAFS），用于开发场景地震，设定区域建筑法规以及设定地震保险率。尽管无法准确预测主要地震的时机，但可以从当今地壳变形的大地测量中准确估计矩量。目前在北美西部连续运行的GPS站的700个阵列并不能完全解决沿主要断层的地壳变形梯度（应变），因为平均站间距太大。这项研究是通过计算和建模在西部北美Insar Insar Insar Insar Insar Insar Consortium（Winsar）和阿拉斯加卫星设施的合成孔径雷达数据（SAR）来完善地壳变形测量值。这涉及以近自动方式在0.5 km空间分辨率下的大型（1000公里）地壳变形网格的产生和档案。这笔赠款的资金正在支持两个博士学位。 Sio和UTEP（西班牙裔服务学院）的学生正在用于进一步发展本科和研究生课程。这笔资金也被用来开发？如何工作？在全国各地展出的IRIS Active Earth Interack亭中使用的模块。此外，还使用资金将GMTSAR软件移至GMT分销系统中，在该系统中可供全球15,000名用户使用。我们将所有高分辨率矢量变形数据和地图分发给科学界，并在UNAVCO上存档结果。