INDUCED SEISMICITY Fluid-induced aseismic fault slip outpaces pore-fluid migration
INDUCED SEISMICITY Fluid-induced aseismic fault slip outpaces pore-fluid migration
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DOI：
10.1126/science.aaw7354
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发表时间：
2019-05-03
期刊：
影响因子：
56.9
通讯作者：
Viesca, Robert C.
中科院分区：
文献类型：
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作者：
Bhattacharya, Pathikrit;Viesca, Robert C.
地下流体注入引起的震群通常被认为发生在因孔隙流体压力增加而不稳定的断层上。然而，流体注入也可能激活无震滑动，这可能超过孔隙流体迁移并将地震触发应力变化传递到流体加压区域之外。我们测试了这一理论预测的数据来自流体注入实验，激活和测量缓慢，asepressive滑动预先存在的，浅断层。我们发现，孔隙压力和滑动历史意味着一个断层，其强度是产品的滑动削弱摩擦系数和当地的有效正应力。使用耦合剪切破裂模型，我们推导出的活动变形断层的流体力学参数的约束。推断的非绝热破裂前沿传播速度快，比加压孔隙流体的扩散更大的距离。
Earthquake swarms attributed to subsurface fluid injection are usually assumed to occur on faults destabilized by increased pore-fluid pressures. However, fluid injection could also activate aseismic slip, which might outpace pore-fluid migration and transmit earthquake-triggering stress changes beyond the fluid-pressurized region. We tested this theoretical prediction against data derived from fluid-injection experiments that activated and measured slow, aseismic slip on preexisting, shallow faults. We found that the pore pressure and slip history imply a fault whose strength is the product of a slip-weakening friction coefficient and the local effective normal stress. Using a coupled shear-rupture model, we derived constraints on the hydromechanical parameters of the actively deforming fault. The inferred aseismic rupture front propagates faster and to larger distances than the diffusion of pressurized pore fluid.