Fault growth by segment linkage in seismically active settings: Examples from the Southern Apennines, Italy, and the Coast Ranges, California

Most models for fault growth and scaling are based on analysis of faults wh ich display dip-slip (i.e. reverse,:normal) and strike-slip kinematics; by contrast, little information is derived from faults displaying oblique-slip kinematics. Observations on mesoscopic transpressional faults from the Sal inian Block of California and transtensional faults from the Southern Apenn ines of Italy reveal a complex kinematic history of fault propagation. Faul ts initially nucleate:: as: isolate segments, which are later kinematically and mechanically linked via development of diffuse deformation zones and/o r localised oblique connecting splays. The geometry of observed mesoscopic faults is similar to that of the host, larger structures, thus suggesting t hat the produced fault patterns are scale independent. Moreover, the overpr inting relationships among minor fault-related fabrics: permit to define a relative chronology within fault arrays, thus enabling a general sequence o f structural:stages to be correctly established. Based on minor fabrics and their overprinting relationships,:a kinematic deformation model of fault g rowth by segment linkage is presented, which may have a wide applicability in the field of seismic hazard evaluation. (C) 1999 Elsevier Science Ltd. A ll rights reserved.