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F. Pepe et al. / Geomorphology 303 (2018) 191–209 193

Fig. 1. A) Schematic geological map of Favignana Island simplified from Abate et al. (1997) with locations of the investigated areas (Punta Faraglione and Punta Fanfalo). Legend:
1) Continental detritus; 2) continental sand and silt (Pleistocene-Holocene); 3) conglomerates and breccias (Pleistocene-Holocene); 4) fossiliferous conglomerates and bioclastic
calcarenites (Early Pleistocene); 5) biolithite (algae and corals), bioclastic calcarenites and calcirudites (Early-Middle Miocene); 6: fossiliferous carbonates (Late Triassic-Early Jurassic).
Shaded relief based on bathymetric data from the nautical chart “Litorale da Trapani a Marsala e Isole Egadi”, at scale 1:50,000. Inset 1: simplified tectonic map of north-western Sicily
and its offshore prolongation simplified from Catalano et al. (1996). Legend: TS: Trapanese-saccense platform units; FB: Oligo-Miocene deformed Foreland basin; PU: Panormide
platform units; MB: Early Pliocene-Late Miocene wedge top basin deposits; PB: Early Pleistocene-Late Pliocene wedge top basin deposits; QD: Quaternary overlap. Inset 2: position of
boulders collected in the Punta Fanfalo coastal area for bulk density measurement (Fig. 8); x–z, traces of inset a in Fig. 8. B) Topographic and bathymetric profiles across the coastal
zones of Punta Faraglione (a, b, c) and Punta Fanfalo (d, e, f).

terms of size, shape and distance from the coastline were analyzed. In dip relating to, respectively, the Punta Faraglione and Punta Fanfalo
particular, their axes (A, B and C, where A is the major axis, B the medi- rock coasts.
um and C the minor one, corresponding to boulder's thickness, Fig. 2a) The analysis of the fracture set orientation data was carried out by
as well as their distance from the shoreline, and the azimuthal angle using the Stereonet 9 software (Allmendinger et al., 2012). A prelimi-
of the A-axis referring to each boulder were measured. Moreover, boul- nary selection of the sets was made from contour plot of fracture
der locations were mapped using a hand-held GPS device with an accu- poles based on their statistical concentration (Kamb contouring). Sub-
racy of ±2 m. sequently, sets characterized by the lowest computable dispersion indi-
A second survey in March 2017 provided additional measurements ces were identified by using the trial-and-error method. This is a
of sockets as well as the azimuth and dip of bedding; also, the fracture method of problem solving, characterized by repeated, varied attempts
network formed in the Lower Pleistocene grainstones outcropping in which are continued until success, or until the agent stops trying. Specif-
the surveyed rocky coast. Rock samples were also taken from boulders ically, the Fisher “k” value (Fisher, 1953) was computed for a great
selected on the basis of their lithofacies and thickness (C axis), in number of preliminary-selected sets, and then the fracture sets charac-
order to describe their lithologies and carry out laboratory measure- terized by the highest k value were selected. The Von Mises Circular Dis-
ments of bulk densities. tribution (Odling, 1997, and references therein) was also calculated to
perform statistical analysis of their direction.
The spacing of some fracture sets was computed using the scan-line
3.2. Fracture analysis method. In particular, the spacing was calculated as the inverse value of
fracture intensity by using the mathematical relation: S = 1 / P10. Sub-
Quantitative analyses of bed-perpendicular fracture sets' orienta- sequently, the real value of the spacing was obtained by applying the
tions were performed on 117 and 43 measurements of azimuth and Terzaghi correction (Terzaghi, 1965).