Loading-Induced Earth's Stress Change over Time

This is a preliminary database of loading-induced stress changes on the Earth from 2000 to 2017 in a global scale and at various depths. Five loading forces that would generate stress changes on the Earth are considered: hydrological loading, atmospheric pressure, ocean water (including tides and non-tidal variation), solid Earth tides and postglacial rebound (PGR). The loading forces are quantified using the terrestrial water storage (TWS) inferred from GRACE solutions, the ECMWF surface atmospheric pressure model, the TPXO 7.2 ocean tide solutions, CMEMS sea level anomaly model, tidal forces computed by the SPOTL package, and the ICE-5G glacial history model, respectively. The loading masses are assumed to distribute within a thin layer (relative to the Earth’s radius) on the Earth’s surface, and are used to calculate the Earth’s stress responses through a spherical spectral method. Based on the different time scales of the loading forces, an incompressible viscoelastic Earth model is adopted for PGR and a compressible elastic one is adopted for the other forces. The stress database could motivate more comprehensive studies to seek clearer physical insights on triggering mechanisms of various tectonic events, such as earthquake, non-volcano tremor, slow slip event and volcano. The physical framework we have established in the stress calculation could be a useful tool for updating and improving the stress estimates in the future and could facilitate more comprehensive studies of elastic/viscoelastic parameters and physical states of the Earth’s interior at various time scales and length scales. Please refer to Lu et al. (2018, JGR) for the detailed methods and parameters used to calculate the loading-induced stress. Currently, the stress results are output on 1x1 degree grids, and at depths of 0 km, 19 km, 50 km, and 100 km.

本数据集为2000年至2017年全球尺度下、不同深度的地球载荷诱发应力变化初步数据库。本研究考虑了五种可引发地球应力变化的载荷驱动力：水文载荷（hydrological loading）、大气压强、海洋水体（含潮汐与非潮汐变化）、固体地球潮汐以及冰后回弹（postglacial rebound, PGR）。上述载荷驱动力分别通过以下数据与模型量化：由GRACE解推算得到的陆地水储量（terrestrial water storage, TWS）、ECMWF地表大气压强模型、TPXO 7.2海洋潮汐解、CMEMS海平面异常模型、由SPOTL软件包计算得到的潮汐力，以及ICE-5G冰川历史模型。本数据集假设载荷质量以薄层形式（相对于地球半径而言）分布于地球表面，并通过球谐谱方法计算地球的应力响应。根据各载荷驱动力的不同时间尺度，冰后回弹（PGR）采用不可压缩黏弹性地球模型，其余载荷驱动力则采用可压缩弹性地球模型。该应力数据库可推动更深入的综合研究，以更清晰地阐明地震、非火山震颤、慢滑事件以及火山等各类构造事件的触发机制物理本质。本研究在应力计算中构建的物理框架，可为未来更新与优化应力估算提供实用工具，同时也有助于开展多时间尺度与空间尺度下地球内部弹性/黏弹性参数及物理状态的综合研究。有关载荷诱发应力的具体计算方法与参数设置，请参阅Lu等人（2018年，JGR）的相关研究。目前，该应力结果以1°×1°网格形式输出，计算深度涵盖0 km、19 km、50 km与100 km。