Integrating Geologic, Geodetic, and Coastal Tide Gauge Observations with 100-year Vertical Deformation Models of California Earthquake History

将地质、大地测量和沿海验潮观测与加州地震历史 100 年垂直变形模型相结合

• 批准号: 0838252
• 负责人: Bridget Smith-Konter
• 金额: $ 23.08万
• 依托单位: University of Texas at El Paso
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-15 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838252&HistoricalAwards=false
• 关键词: Integrating; Geologic; Geodetic; Coastal; Tide

This project investigates earthquake-induced vertical deformation using a synthesis of coastal tide gauge, geodetic, and geologic data of the Pacific-North American plate boundary. While the growing archive of space geodetic data in this region provides precise deformation measurements with a high degree of spatial coverage, these data supply only a 15-year record of crustal motions and therefore only weakly constrain time-dependence of crustal motions. Geologic data provide a 1000-year averaged record of deformation, however these data are often sparsely located and can have large uncertainties. Alternatively, sea level change has been continuously recorded along the California coastline at several tide gauge stations for over the past 50-100 years. These stations provide a temporal record of sea level change, generally attributed to post-glacial rebound and ocean climate phenomena. However, geologic processes, including displacements from large earthquakes, have also been shown to produce sea level variations, as vertical interseismic strain accumulation can contribute uplift and subsidence rates of 1-3 mm/yr. Using coastal tide gauge time series data, this project is exploring the correlation between sea level variations and estimates of vertical displacements produced by a three-dimensional earthquake cycle deformation model that is constrained by geologic slip rates, geodetic velocities, and historical seismic data along the San Andreas fault system. First order vertical deformation estimates derived from geologically and geodetically constrained models are highly compatible with long-term sea level trends, however further analysis is needed to thoroughly explore model parameter space and investigate sources of misfit and unmodeled phonomena. The project will integrate 100-year coastal tide gauge data (Permanent Service for Mean Sea Level), geodetic data (EarthScope Plate Boundary Observatory continuous GPS and InSAR) spanning the last 15 years, and a new geologic database (Southern California Earthquake Center Geologic Vertical Motion Map).This study investigates the long-term role of tectonic deformation on sea level change recorded over the past 100 years along the California coastline. In doing so, these research activities contribute to the objectives of NSF?s EarthScope Initiative by further advancing our understanding of fault system crustal dynamics, earthquake hazards, and data synthesis. The data and model products generated by this investigation will provide an enhanced infrastructure for education and public awareness of both past and present earthquake hazards in California. Furthermore, because a major California earthquake has the potential for massive economic and human loss, quantitative seismic hazard estimates, which rely on an accurate characterization of tectonic motions in California, are critical to the advancement of earthquake science.

本计画利用太平洋-北美板块边界的海岸验潮仪、大地测量和地质资料，研究地震引起的垂直形变。虽然这一区域空间大地测量数据的档案不断增加，提供了具有高度空间覆盖范围的精确变形测量数据，但这些数据只提供了15年的地壳运动记录，因此对地壳运动的时间依赖性的制约很小。地质数据提供了1000年的平均变形记录，但这些数据往往是稀疏的位置，可以有很大的不确定性。另外，在过去的50-100年里，沿着加州海岸线的几个验潮站连续记录了海平面的变化。这些观测站提供了海平面变化的时间记录，通常归因于冰后期反弹和海洋气候现象。然而，地质过程，包括大地震引起的位移，也被证明会产生海平面变化，因为垂直的地震间应变积累会导致1-3毫米/年的上升和沉降速率。该项目利用沿海验潮仪时间序列数据，探讨海平面变化与三维地震周期变形模型产生的垂直位移估计值之间的相互关系，该模型受地质滑动率、大地速度和圣安德烈斯断层系统沿着历史地震数据的制约。一阶垂直形变估计来自地质和大地测量约束模型是高度兼容的长期海平面趋势，但需要进一步的分析，以彻底探索模型参数空间和调查来源的失配和未建模的phonomena。该项目将整合100年沿海验潮数据（平均海平面常设服务处），大地测量数据（EarthScope板块边界观测站连续GPS和干涉合成孔径雷达）跨越过去15年，和一个新的地质数据库（南加州地震中心地质垂直运动图）。沿着加州海岸线记录的过去100年来构造变形对海平面变化的长期作用。在这样做，这些研究活动有助于NSF的目标？通过进一步推进我们对断层系统地壳动力学、地震灾害和数据综合的理解，本次调查产生的数据和模型产品将为加州过去和现在的地震灾害的教育和公众意识提供增强的基础设施。此外，由于加州大地震有可能造成巨大的经济和人类损失，定量的地震危险性估计，这依赖于一个准确的描述构造运动在加州，是至关重要的地震科学的进步。