The growth of normal faults by segment linkage

Abstract

Abstract Fault growth is widely described using a scaling law between maximum displacement ( D ) and length ( L ), of the form D = cL n . This expression defines a model of fault growth by radial propagation from a single seed fracture or fault. This paper presents geometrical and kinematic evidence from a set of exceptionally well exposed normal faults in Utah for an alternative model of fault growth. This model is referred to as growth by segment linkage, and involves the propagation and linkage of independent fault segments on ascending length scales. The evidence presented focuses on the geometry and displacement variation in the region of relay structures, and on local scaling relationships between D and L . The D - L data from 97 faults in the study area range over three orders of magnitude, and show a general trend to increasing D for increasing L . There is a large scatter in the data, similar to that recognized in previous D - L compilations. It is argued that the scatter cannot be attributed either to measurement errors or to variation in mechanical properties. Instead, we argue that the model of growth by segment linkage provides a simple explanation of this scatter, and propose that the process of segment linkage may explain scatter in other datasets.