Experimental investigation on fluid-induced slip behavior of fault filled with fault gouge

Abstract

Fault zones are usually filled with fault gouge and accompanied by fault water. The coupled effect of fault gouge and water significantly impacts the slip behavior of the fault, which may weaken the fault structure and further induce rupture propagation and earthquakes. In this study, we carried out a laboratory experiment to investigate the fluid-induced slip behavior of fault filled with gouge. The friction evolution characteristic associated with fluid pressure and effective stress was investigated during the slip process. In addition, the role transformation process of the gouge on the slip behavior of fault was revealed. The experimental result indicates that the friction on the filled fault surface is significantly affected by fault gouge. The rupture of the gouge promotes fault slip and the fluid pressure plays a vital role in the initiation of fault slip. The fault gouge enhances the shearing strength of the fault and acts as a barrier before the initial slip under fluid injection. Nevertheless, the fault gouge would accelerate the fault slip and transform into lubricant after the initial slip.

Keywords

• Fault gouge
• Fluid
• Slip behavior
• Friction
• Shear strength