Numerical modelling of spatially and temporally distributed on-fault induced seismicity: implication for seismic hazards
Numerical modelling of spatially and temporally distributed on-fault induced seismicity: implication for seismic hazards
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DOI：
10.1007/s40789-022-00560-7
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发表时间：
2023-01
影响因子：
8.3
通讯作者：
A. Sainoki;A. Schwartzkopff;Lishuai Jiang;H. Mitri
中科院分区：
文献类型：
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作者：
A. Sainoki;A. Schwartzkopff;Lishuai Jiang;H. Mitri
诱发地震活动与引起深部地应力变化的各种工程活动密切相关。因此，有必要估计和减轻相关风险。在过去，各种模拟方法已被开发和应用于诱发地震活动性分析，但仍然有一个根本的差异，模拟结果和现场观测的地震事件的空间分布和频率。本研究的目的是开发一种方法来模拟空间分布的断层地震活动，同时再现复杂的应力状态的断裂带。因此，一个等效的连续介质模型的基础上，在一个离散的裂缝网络的断层损伤区，采用裂纹张量理论。在模型中心模拟断层核作为不连续平面。利用该模型，首先通过在模型外边界上施加牵引力来模拟断裂带中具有应力异常的非均匀应力状态。随后，断层面上的有效正应力以逐步的方式减小以诱发滑动。用b值和其他震源参数对模拟结果进行了验证，表明该模型能够再现断层地震活动的时空分布。对这些参数的进一步分析表明，在大地震发生前，地震频度-震级分布发生了变化。这种变化被认为是一致的，与现场观察，从而表明这种模拟方法在评估各种工程项目的地震灾害的风险的潜在用途。
Induced seismicity is strongly related to various engineering projects that cause anthropogenic in-situ stress change at a great depth. Hence, there is a need to estimate and mitigate the associated risks. In the past, various simulation methods have been developed and applied to induced seismicity analysis, but there is still a fundamental difference between simulation results and field observations in terms of the spatial distribution of seismic events and its frequency. The present study aims to develop a method to simulate spatially distributed on-fault seismicity whilst reproducing a complex stress state in the fault zone. Hence, an equivalent continuum model is constructed, based on a discrete fracture network within a fault damage zone, by employing the crack tensor theory. A fault core is simulated at the center of the model as a discontinuous plane. Using the model, a heterogeneous stress state with stress anomalies in the fault zone is first simulated by applying tractions on the model outer boundaries. Subsequently, the effective normal stress on the fault plane is decreased in a stepwise manner to induce slip. The simulation result is validated in terms of theb-value and other seismic source parameters, hence demonstrating that the model can reproduce spatially and temporally distributed on-fault seismicity. Further analysis on the parameters shows the variation of frequency-magnitude distribution before the occurrence of large seismic events. This variation is found to be consistent with field observations, thus suggesting the potential use of this simulation method in evaluating the risk for seismic hazards in various engineering projects.