Duplex

Duplex: Most commonly, a system of thrust faults bounded by two parallel to subparallel subhorizontal thrusts separated by a deformed interval dominated by smaller imbricate faults that connect the two master faults. The imbricates have the same sense of movement as the master faults. The upper fault is the roof thrust: the lower is the floor thrust. Duplexes are thought to be the mechanism by which a fault changes to a new level. Duplexes may also form in normal and strike-slip fault zones.