Displacement and stress fields around a fault jog: Effects on fault mechanics

We consider a fault surface which differs slightly from a plane due to a jog. The fault is placed in an elastic space and is subject to a uniform stress field. The orientation of the fault is such that the normal traction is greater on the jog determining a higher static friction. A considerable increase in friction and the formation of a strong asperity can occur due to repeated slip episodes on the fault. Slip produces an elastic deformation of the fault faces in correspondence of the asperity, causing an increase in normal traction and hence in friction. This process can be described as a tensile Somigliana dislocation, accompanied by partial fracturing of the fault face material, which can produce fault gouge.