“…A brief summary of field studies reveals that polygonal fault systems have been documented in: (1) Paleogene mudstones in Belgium (Henriet et al, 1988(Henriet et al, , 1991Verschuren, 1992;Dehandschutter et al, 2004Dehandschutter et al, , 2005a; (2) Cretaceous chalk in France and the UK (Hibsch et al, 2003); (3) Cretaceous chalk in Egypt (Tewksbury et al, 2014); (4) Jurassic sandstones in the US (Antonellini and Mollema, 2015); and (5) Cretaceous to Paleogene carbonates, cherts, and marls in Italy (Petracchini et al, 2015). Whilst earlier studies examining polygonal fault systems in the field mapped faults as discrete slip surfaces (Henriet et al, 1988(Henriet et al, , 1991Verschuren, 1992;Dehandschutter et al, 2004Dehandschutter et al, , 2005a, recent work suggests that "individual" polygonal faults actually consist of dense clusters of slip surfaces (Tewksbury et al, 2014;Antonellini and Mollema, 2015;Petracchini et al, 2015). If the polygonal faults mapped in this study consist of slip surfaces with displacements below the seismic resolution (<10 m), we would underestimate the total strain in the system.…”