## 6 Fault Trench Analyses at the Base of the Scarp  
A small fault trench was excavated in 2002, adjacent to the fault-scarp, after detailed geomorphological, geophysical, and topographic (5 cm/pixel DEM) analysis of the Sta. Eugenia fault segment [20; 35]. The trench was dug with a backhoe excavator perpendicular to the fault scarp, with a N150\({}^{\circ}\) E orientation. Due to the absence of datable material, the trenching results were only preliminarily reported in a post-conference field trip of the Sixth International Congress of the International Union of Geomorphology (IAG) held in Spain in 2005 [23]. So, it is in this work that the fault trench of the SCF is fully described. The purpose was to compare and relate, if possible, the different identified lichen ribbons with probable exposure events of the fault plane recorded as colluvial wedges within the trench. The trench was 16 m long, 4 m wide and 3.5 m deep, and it was excavated only in the softer sedimentary filling of the hanging wall of the fault (Figure 12). The SW limit of the \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Site** & _Thallus n*_ & **Lichen Sp.** & **Ribbon** & **Size (mm)** & **Age 1 (Year)** & **Age 2 (Year)** \\ \hline HOUSE & 4 & _A. calcareous_ & B1 & 7.07 & 1979 & 1997 \\ HOUSE & 15 & _A. calcareous_ & B1 & 11.36 & 1959 & 1976 \\ HOUSE & 5 & _A. calcareous_ & B1 & 12.51 & 1954 & 1971 \\ HOUSE & 3 & _A. calcareous_ & B1 & 12.87 & 1953 & 1969 \\ HOUSE & 2 & _A. calcareous_ & B1 & 13.97 & 1945 & 1964 \\ HOUSE & 1 & _A. calcareous_ & B1 & 14.49 & 1941 & 1961 \\ FENCE & 8 & _A. calcareous_ & B1 & 16.34 & 1929 & 1957 \\ \hline
**Average date** & & & & **1949 \(\pm\) 9.9** & **1966 \(\pm\) 15.4** \\ \hline FENCE & 14 & _A. calcareous_ & B2 & 13.38 & 1950 & 1962 \\ HOUSE & 16 & _A. calcareous_ & B2 & 13.57 & 1949 & 1962 \\ HOUSE & 12 & _A. calcareous_ & B2 & 15.00 & 1943 & 1954 \\ HOUSE & 13 & _A. calcareous_ & B2 & 19.46 & 1923 & 1931 \\ HOUSE & 11 & _A. calcareous_ & B2 & 20.23 & 1919 & 1927 \\ FENCE & 33 & _A. calcareous_ & B2 & 20.80 & 1916 & 1924 \\ FENCE & 34 & _A. calcareous_ & B2 & 22.55 & 1909 & 1916 \\ FENCE & 35 & _A. calcareous_ & B2 & 23.44 & 1904 & 1911 \\ HOUSE & 10 & _A. calcareous_ & B2 & 24.28 & 1901 & 1907 \\ HOUSE & 9 & _A. calcareous_ & B2 & 27.38 & 1887 & 1891 \\ FENCE & 36 & _A. calcareous_ & B2 & 27.40 & 1886 & 1891 \\ HOUSE & 17 & _A. calcareous_ & B2 & 28.50 & 1881 & 1885 \\ HOUSE & 24 & _A. calcareous_ & B2 & 45.64 & 1804 & 1797 \\ HOUSE & 25 & _A. calcareous_ & B2 & 45.65 & 1804 & 1797 \\ HOUSE & 22 & _A. calcareous_ & B2 & 47.88 & 1793 & 1786 \\ HOUSE & 20 & _A. calcareous_ & B2 & 51.14 & 1779 & 1769 \\ \hline
**Average date** & & & & **1855 \(\pm\) 52.7** & **1841 \(\pm\) 56.0** \\ \hline HOUSE & 7 & _A. calcareous_ & B3 & 8.80 & 1971 & 1986 \\ FENCE & 38 & _A. calcareous_ & B3 & 10.21 & 1965 & 1979 \\ HOUSE & 19 & _A. calcareous_ & B3 & 10.94 & 1961 & 1975 \\ FENCE & 37 & _A. calcareous_ & B3 & 13.61 & 1949 & 1961 \\ HOUSE & 10 & _A. calcareous_ & B3 & 13.96 & 1948 & 1960 \\ HOUSE & 18 & _A. calcareous_ & B3 & 14.46 & 1945 & 1957 \\ FENCE & 40 & _A. calcareous_ & B3 & 14.84 & 1944 & 1955 \\ FENCE & 41 & _A. calcareous_ & B3 & 14.98 & 1911 & 1954 \\ HOUSE & 6 & _A. calcareous_ & B3 & 21.97 & 1879 & 1918 \\ FENCE & 42 & _A. calcareous_ & B3 & 37.17 & 1842 & 1841 \\ FENCE & 43 & _A. calcareous_ & B3 & 59.43 & 1741 & 1727 \\ FENCE & 44 & _A. calcareous_ & B3 & 59.66 & 1740 & 1725 \\ \hline
**Average date** & & & & **1781 \(\pm\) 75.2** & **1763 \(\pm\) 79.9** \\ \hline \end{tabular}
\end{table} 
Table 3: Measurements of Aspicilia calcarea in the bedrock fault scarp. Age 1 corresponds to the direct application of the obtained mean growth rates for vertical populations in the Sencelles and Sta. Eugenia Cemeteries (0.22 mm/yr). Age 2 corresponds to the average date (calendar age) resulting from the application of the obtained mean LGR linear regression function (y = \(-\)4.829x + 2007) shown in Figure 10. Average years and uncertainty (standard deviation) are shown for each analyzed ribbon (B1, B2, B3).