## 5 Lichen Growth Rates: LGR Curves for the Zone
Figure 9: XY dispersion graphics showing the best-fit linear regression lines and corresponding equation for selected vertical populations of lichens from the three cemeteries (**a**) and the cemented of Sta. Maria del Cami within the Inca Plain displaying vertical and horizontal lichen populations (**b**). Rose diagrams show dominant orientations of the measured lichen specimens. In this way, the more suitable populations for this study are those found on vertical surfaces from the Sta. Eugenia and Sencelles centeries with a N-NW orientation, which in  
Figure 10: XY dispersion graphics showing the best-fit linear regression lines and corresponding equations for vertical (V) and horizontal (H) lichen populations in the cemeteries placed on the trace of the Sencelles fault. Rose diagrams show the dominant surface orientation of the measured lichen specimens. fact are the more abundant ones (Figure 10). The vertical populations of _A. radiosa_ result in mean LGRs of 0.14-0.19 mm/yr, whilst those of _A. calcarea_ are of 0.23-0.30 mm/yr. On the contrary, horizontal lichen populations show LGRs up to 0.26 mm/yr for _A. radiosa_ and 0.35 mm/yr for _A. calcarea_ (Table 1). These LGRs are slightly higher than those proposed for _A radiosa_ in SE Spain (0.25 mm/yr), where annual rainfall rates are lower (c. 360 mm/yr) [5; 7; 13]. In our study, the Manusoleum of Mr. [PERSON] (1853 CE) and the tombstone of Mr. [PERSON] (1850 CE) provided specimens of larger size in vertical (42.6 mm) and horizontal (59.8 mm) surfaces, respectively. In Sencelles, the stone pedestal of a large iron cross from 1897 CE in the lower part of the cometary provided the largest lichen sizes for horizontal (101.7 mm) and vertical (42.9 mm) populations (see Figure 7). Besides obtaining mean numerical LGRs from the direct relationships between lichen size and inscribed dates, all the analyzed populations were subjected to statistical analyses to obtain mathematical functions describing annual lichen growth (Tables 2 and 3). In all cases, we selected the simplest best-fit linear regressions with correlation rations (R\({}^{2}\)) over 0.8 and in many cases up to 0.95 (Figure 10). Although in some lichen populations power and second-order polynomial functions displayed slightly better correlation ratios, we decided to select the linear regressions to achieve homogeneity of the results (Figure 10). The obtained functions were used to calculate the exposure age for the different lichen ribbons of the bedrock fault scarp, resulting in similar and coherent dates in the two analyzed species (Tables 2 and 3). Eventually, we calculated a mean regression equation for the populations of _A. radiosa_ in the two cemeteries, since it was the lichen species with a better fit to the measurements taken in the fault scarp (Figure 11). The application of the obtained linear function for vertical populations of _A. radiosa_ to the fault scarp ribbons resulted in average dates of 1950 \(\pm\) 16.7 CE for the basal ribbon B1, 1852 \(\pm\) 40.3 CE for ribbon B2 and 1773 \(\pm\) 80.5 CE for the upper ribbon B3 (_Age 2_: Table 2). The obtained functions for _A. calcarea_ resulted in similar dates of 1966 \(\pm\) 15.4 CE for the basal ribbon B1, 1849 \(\pm\) 56.2 CE for ribbon B2 and 1763 \(\pm\) 79.7 CE for the upper ribbon B3 (_Age 2_: Table 3). The calculation of direct numerical ages provides similar average dates using both species (_Age 1_: Tables 2 and 3). These results clearly indicate that the exposure date of the second ribbon (B2) lies within the range (1841-1855 CE) of the 1851 CE Palma earthquake [20; 36]. Consequently, this second fault ribbon can be considered as a coseismic feature, but its characterization as a primary or secondary faulting feature is discussed in the following sections. Curiously, the average ages of the upper ribbon (B3) lie within the