Different-Scale Heterogeneities in Segments of Active Faults and Their Influence on Slip Modes

Abstract— The paper presents some multidisciplinary research results on the structure of slip surfaces in segments of tectonic faults in the Baikal region and Mongolia. The properties of subsurface (modern) and deep slickensides exposed after many-kilometer denudation of the Earth’s upper crust are studied at different levels—from macroscale to nanocrystals. Other types of heterogeneities characterizing the structure of fault slip zones are also considered. The presented data indicate a heterogeneous structure of tectonic faults. Their slip zones show both low-friction regions where strong mineral phases are replaced by weak minerals and potentially unstable spots with high friction resistance. Results of the comprehensive study of geological conditions under which different-scale heterogeneities emerge in exhumed fault segments should be taken into account when developing rock mass models suitable for numerical simulation of earthquake preparation processes at the micro-, meso- and macroscales.