Numerical modeling of fault rupture propagation through two-layered sands

The fault rupture propagation phenomenon, spreading from the base rock through different layers of soil, is a matter of concern in many natural and man-made soil structures. The focus of this paper is to investigate reverse fault rupture propagation through two layers of sand deposits by means of numerical modeling. For this purpose, analyses are carried out for different permutations of the three typical materials: dense sand, medium dense sand and loose sand, considering five fault dip angles, 30, 45, 60, 75 and 90 degrees. The validity of numerical model was verified by simulating an experimental model of homogeneous soil layer subjected to reverse faulting. Further to the general trends found in fault rupture propagation in a single layer of soil, special attentions are devoted to the refraction of fault path in the interface of two materials as well as its concavity in the continuation. Moreover, four patterns of fault rapture propagation in two-layered sands, depending on their arrangements and fault dip angles, were concluded from the results.