Experimental study of the evolution of fault gouge in layered sand–clay sequences

Schmatz, Joyce
Vrolijk, Peter
Urai, Janos L. ORCIDiD
Giese, Steffen
Ziegler, Martin ORCIDiD
Zee, Wouter van der
Philipp, Sonja
Leiss, Bernd ORCIDiD
Vollbrecht, Axel
Tanner, David ORCIDiD
Gudmundsson, Agust

DOI: https://doi.org/10.23689/fidgeo-1890
Philipp, Sonja; Leiss, Bernd; Vollbrecht, Axel; Tanner, David; Gudmundsson, Agust (Ed.), 2006: Experimental study of the evolution of fault gouge in layered sand–clay sequences. , Universitätsverlag Göttingen, S., DOI: https://doi.org/10.23689/fidgeo-1890. 
Schmatz, Joyce; Vrolijk, Peter; Urai, Janos L.; Giese, Steffen; Ziegler, Martin; Zee, Wouter van der, Philipp, Sonja; Leiss, Bernd; Vollbrecht, Axel; Tanner, David; Gudmundsson, Agust (Ed.),2006: Experimental study of the evolution of fault gouge in layered sand–clay sequences. In: , Universitätsverlag Göttingen, DOI: https://doi.org/10.23689/fidgeo-1890. 

Abstract

This study focuses on clay smear processes during fault gouge evolution in sand-clay sequences at depths up to 2 km. A clay-rich fault gouge can dramatically lower the fault’s permeability, and prediction of this process is therefore relevant in groundwater modelling and hydrocarbon geology (Fulljames et al. 1997, Yielding et al 1997, van der Zee et al. 2003, 2005). We constructed an ‘underwater’ sandbox to deform layered sand-clay models of 20 × 40 × 20 cm above a 70°-dipping rigid basement fault. The experiments are run completely watersaturated to allow deformation of wet clay and cohesionless sand. The basement fault moves at 20 to 120mmh−1 to a maximum offset of 60 mm. We use quartz sand with grain size between 0.1 to 0.4mm and an illite-rich clay with a water content between 28 and 55 wt.%. Water content of the clay is used to control its shear strength and state of consolidation...