Geometric pattern, rupture termination and fault segmentation of the Dixie Valley—Pleasant Valley active normal fault system, Nevada, U.S.A.

Abstract

Active fault systems of both interplate and intraplate settings clearly show patterns of segmentation. Fault segmentation, therefore, is very important for understanding fault behavior and assessing seismic hazard. The complexity of geometric patterns along fault systems has a strong influence on the propagation of earthquake ruptures, because it can form structural heterogeneities that tend to inhibit rupture propagation. This implies that there should be relations between fault segmentation and the complexity of fault geometry. The active normal faults of the Dixie Valley—Pleasant Valley system provide an excellent example to study such relations and to establish the geometric method of normal fault segmentation in the Basin and Range province. Studies of fault segmentation in the Dixie Valley—Pleasant Valley fault system indicate that there are changes of both geometric pattern and geomorphic character in the area of the segment boundary. The characteristics of segment boundaries on normal faults of the Dixie Valley—Pleasant Valley system can be explained in terms of the nature of rupture propagation and termination. These changes may be helpful criteria for distinguishing normal fault segmentation at least in the Basin and Range province.