The Mechanics of Fractal Fault Gouge

9304388 PI将开发颗粒层摩擦的微观力学模型，其中包括颗粒之间的粉碎、速率和状态摩擦。该模型将通过使用改进的最先进的土力学程序的数值模拟以及最近关于层厚度和颗粒尺寸分布的影响的实验室研究来指导，并添加了关于法向应力影响的补充实验。这项工作的动机是将断层带宽度与断层稳定性联系起来的地震学证据，利用地震层析成像和圈闭模式研究断层带内部结构的最新进展，以及最近关于海底成熟转换断层上地震的缓慢前兆的证据，这意味着实验室和现场之间的摩擦参数发生了显著的比例变化。***

9304388 Sammis The PI will develop a micromechanical model for the friction of granular layers which incorporates comminution and rate and state-friction between the particles. This modeling will be guided by numerical simulations using a modified state-of-the-art soil mechanics program, and by recent laboratory studies on the effects of layer thickness and particle size distribution, adding complimentary experiments on the effect of normal stress. This work is motivated by seismological evidence relating fault zone width to fault stability, by recent advances in using seismic tomography and trapped modes to investigate the internal structure of fault zones, and by recent evidence for slow precursors to earthquakes on mature transform faults on the ocean floor which imply a significant scaling change of friction parameters between the laboratory and the field. ***