GNSS风暴潮负荷形变与地震触发模式研究

Storm surge is characterized by anomalous rising and falling phenomena of sea levels due to severe atmospheric disturbances and usually causes short-term water-increasing and water-decreasing effects of local atmosphere, ocean and land. A huge mass of water increase/loss results in elastic deformation of ground and sharp disturbance of stress, and potentially triggers seismic events. In this study, we will precisely extract the 3-D storm surge loading deformation using sub-daily GNSS (Global Navigation Satellite System) time series, model the water-increasing and water-decreasing evolution history of storm surge loading effects, and investigate the corresponding crustal stress adjustment mechanism and regional earthquake triggering patterns. This study not only provides an effective solution for the research of storm surge loading effects and solve the scientific problem of GNSS non-tidal loading deformation, but also provides reasonable basis for the scientific problem of earthquake nucleation mechanisms associated with mass loading and further clarifies the seismogenic patterns of regional fault system.

风暴潮(Storm Surge)是由剧烈大气扰动导致的海平面异常升降现象，其过境通常伴随着大气、海洋和陆地短期的局部增水和失水作用。巨大的增水和失水效应引起地表质量的重新分布，导致地球的弹性负荷变形和地壳应力的急剧扰动，并且有可能触发地震事件。本研究将从精密提取GNSS (Global Navigation Satellite System)台站三维风暴潮负荷形变出发，建模并再现风暴潮负荷效应的增水和失水演化历程，并分析风暴潮负荷效应对地壳应力的调节机制以及区域地震的触发模式。该项研究不仅为风暴潮负荷效应的研究提供有效解决方案，进一步解决利用GNSS研究非潮汐负荷形变的科学难题；而且为负荷相关的地震成核机制的科学难题提供相关合理依据，进一步厘清区域断层系统的孕震模式和发震机制。

对地壳负荷变形的观测与研究是了解陆地水文交互的一种有效途径。本项目设计了一套精密的GNSS数据解算和时间序列分析方案，提取高精度、高动态的风暴潮负荷形变位移；针对密集型GNSS网络，设计了基于ICA/PCA的时变陆地水储量空域反演策略，证实了GNSS可以追踪到极端暴雨事件引起的短期水储量变化；针对稀疏型GNSS网络，设计了基于Slepian方法的时变陆地水储量谱域反演方法，结合气候模式和地理特征证实了GNSS可以用于区域水文动力学过程的分析；将GNSS数据开发成为一种全新的干旱监测工具：GNSS-DSI，全面证实了GNSS观测资料能够用于极端水文事件的监测和评估。本项目的研究工作为进一步认识地表质量负荷效应、陆地水文时空变迁、水文动力学过程、水文气候交互模式等地球物理现象和过程提供重要的观测约束。