Page 13 - LaVecchia_Ferrarini_alii_2007

G. Lavecchia et al. / Tectonophysics 445 (2007) 145–167 157

Table 1 (continued)
n° Y M D H M Lat Lon H Depth Locality Ref. Imx Io Maw Mw SP
58 1968 1 15 1 33 37.817 13.006 34.0 D Belice Valley A&J87 5.2 CD
59 1968 1 15 2 1 37.75 12.983 13.0 D Belice Valley A&J87 CFTI 6.12 5.5 CD
60 1968 1 15 3 18 37.793 12.96 23.0 D Belice Valley A&J87 4.7 CD
61 1968 1 16 16 42 37.857 12.976 36.0 D Belice Valley A&J87 5.2 CD
62 1968 1 25 9 56 37.687 12.966 3.0 S Belice Valley A&J87 5.2 CD
63 1968 9 1 5 2 37.8 13 D Gibellina POS85 55 4.63 CD
64 1970 12 30 5 16 37.7 12.9 D Partanna GG1974 ⁎ 55 4.63 CD
65 1971 4 21 37.714 15.148 S-Et Fondo Macchia AZ2000 80 80 4.8 E
66 1972 12 27 11 45 37.701 13.021 S Menfi LS1972 ⁎ 60 4.83 CS
67 1973 9 21 23 40 37.7 13 D S. Margherita LS1973 ⁎ 55 4.83 CD
68 1975 6 12 19 27 37.45 14.433 D Valguarnera POS85 60 4.56 CD
69 1976 10 12 4 26 37.833 13.067 D Gibellina LS1976 ⁎ 55 4.63 CD
70 1978 1 19 5 15 37.583 14.1 D San Leone LS1978 ⁎ 55 4.63 CS
71 1981 6 7 37.67 12.47 18.1 D Mazara P&AL DBMI04 4.6 4.9 CD
72 1984 10 25 1 11 37.575 15.124 5.9 S-Et Fleri CSI DBMI04 4.7 4.7 E
73 1987 2 2 16 8 37.766 14.702 26.9 D Regalbuto CSI 4.7 CD
74 1987 8 13 7 22 37.9 15.06 35.9 D Maletto P&AL DBMI04 4.03 4.8 U
75 1988 10 28 18 48 37.812 15.068 0.2 S-Et Piano Pernicana OB2001 DBMI04 4.47 E
76 1999 8 30 20 52 37.532 14.638 28.6 D Raddusa CSI 4.9 CD
77 2002 10 29 10 02 37.680 15.100 1.32 S-Et Santa Venerina NE05 4.5 E
Source of data: POS85 (Postpischl, 1985); CFTI (Boschi et al., 2000); CPTI04 (Working Group CPTI, 2004); CSI (Castello et al., 2006); DBMI04
(Stucchi et al., 2007); OB2001 (Obrizzo et al., 2001); R99 (Rigano et al., 1999); ABAR2000 (Azzaro and Barbano, 2000); AZ2000 (Azzaro et al.,
2000a); A&J87 (Anderson and Jackson, 1987); P&AL (Pondrelli et al., 2004); NE05 (Neri et al., 2005b); BAR1897 (Baratta, 1897); LS1972 (La
Sicilia, 1972); LS1973 (La Sicilia, 1973); LS1976 (La Sicilia, 1976); LS1978 (La Sicilia, 1978); GG1974 (Gasparini and Giovani, 1974). The starred
references refer to the events reviewed in this paper. Key: H = depth from instrumental data; Depth = inferred depth range of the seismogenic source
(from instrumental data or from a roughly analysis of the extent of the macroseismic field): D = deep (mid-lower crust) source, S = shallow (upper
crust) source, S-Et = shallow source earthquake associated to the Etna volcanic dynamics. Imx = maximum intensity and Io = epicentral intensity in
MCS (Mercalli–Cancani–Sieberg scale)×10 scale. M w = moment magnitude derived from instrumental data, M aw = moment magnitude derived
from the macroseismic field in the case of the historical earthquakes and through a weighted average procedure which considers both the
macroseismic and the instrumental information in the case of early instrumental and instrumental events (Working Group MPS, 2004). SP =
Seismotectonic provinces defined in this paper: CS = shallow compressional province, CD = deep compressional province, E = Etnean province, T =
tensional province, U = uncertain source depth. The earthquakes in the list with M w and/or M aw ≥ 5.0 are highlighted in bold and the instrumental
data are underlined. All the events (excluding the Etna-associated ones) of the list are projected into the map of Fig. 9.

cover (depthb~8 km) and consequently, the associate contour line in north-eastern Sicily, apparently do not fit
damage, although sometimes quite heavy, affects very this scenario. We suggest that these events (T-signed
small areas (Azzaro and Barbano, 1997; Patanè et al., epicentres in Fig. 9) would be not linked to the com-
2004). Therefore, their macroseismic pattern is easily pressional deformation associated to the SBT, but rath-
distinguishable from those of the events occurring in the er to the upper crust extension which characterizes
same epicentral area, but located at higher depths, the Madonie–Nebrodi–Peloritani area north of the
related to the regional tectonics and felt on much wider Caccamo–Calcavuturo–Troina alignment and which
areas. represents the southward prolongation of the Apennine–
In the map in Fig. 9, all the earthquakes of the Calabrian seismogenic deformation field (Neri et al.,
merged list, with the exclusion of the Etna volcanic 2005a; Scarfi et al., 2005; Pondrelli et al., 2006). In the
events, are projected onto the SBT depth-contour map. merged dataset (Table 1), these events have been labelled
Considering the intrinsic limits of historical data, a as “T”, which stands for “tensional”.
good fit may be observed between the 3D shape of the
SBT, as depicted from its depth-contour lines, and the 5. Sicilian Basal Thrust–Earthquakes association
general northward deepening of the historical earth-
quakes. In fact, the shallow source earthquakes prevail 5.1. Considerations on the likely source of the major
above the 0-to-10 km SBT depth-contour lines and the earthquakes
deep source ones predominate above the 10-to-25 km
depth-contour lines. A few shallow source earthquakes During the last two thousand years, four relative strong
which are located nearly above the 25 km SBT depth- earthquakes (M aw N5.5) have occurred in mainland and