Confluence and intersection of interacting conjugate faults: A new concept based on analogue experiments

Examination of the interaction area of conjugate faults yields evidence of a yet unknown structural pattern. Analogue experiments revealed the evolution of this pattern during the interaction process. A fault propagating towards the highly active section of another conjugate fault becomes increasingly deflected towards the obtuse angle side of the conjugate system while approaching until joining it. During this process, the tip of the curved propagating fault retains its shear sense until immediately before joining with the highly active fault—a process called “confluence” in this report. Under constant remote stress, the deflected fault now becomes dominant. A fault branch splits off at the point where deflection commences, propagating straight ahead of the original direction, and may dissect the former master fault. Alternating activity at both of the faults finally produces the known intersection patterns. Further studies of the proposed concept on natural examples are recommended due to the close geometric similarity of the evolutionary structural stages and natural fault patterns.