Breddin's graph for tectonic regimes

A simple graphical method is proposed to infer the tectonic regime from a f ault and slip data set. An abacus is overlaid on a plot of the rake versus strike of the data. This yields the horizontal principal stress directions and a constraint on the stress tenser aspect ratio, in a manner similar to Breddin's graph for two-dimensional strain analysis. The main requirement i s that one of the principal stress directions is close to the vertical. Thi s method is illustrated on monophase synthetic and natural data, but is als o expected to help sort out multiphase data sets. (C) 2001 Elsevier Science Ltd. All rights reserved.