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86 G. Corti et al.

Sardinia

Tyrrhenian back-arc basin

Campidano
N-Algerian Basin Sardinia Channel

38 Figure 3. Simplified tectonic map of the
Sicily Channel (modified after Tricart et

ics is marked both by the ENE-trending
A A APP
APP Sicily al., 1994). Pliocene–Pleistocene tecton-
P1b C Maghrebides-Sicily-Apennines accre-
GB tionary prism and by contemporaneous
NW-trending rift. The black and red ar-
* NB rows indicate the direction of compres-
Maghrebides Tunisia Pantelleria B sion and extension, respectively. Lines
Vega 3 AB and CD indicate the location of the
seismic profiles reported in Figures 5
36 Malta and 6. The stars indicate the main vol-
canic centers of Linosa and Pantelleria.
* Linosa AP—Adventure plateau; P1b—Pamela
A 1bis well; GB—Graham Bank; NB—
Sicily Channel
Nameless Bank.
Atlas D

34 Pelagian shelf

Sahara Platform
8 10 12 14

the Linosa and Malta grabens. Analogously, syntectonic sedi- farther northwest of Pantelleria within the accretionary prism,
ments filling the tectonic depressions thicken toward the south- testifying to the superposition of extensional structures on com-
east (e.g., Boccaletti et al., 1987, and references therein), even pressional ones (Fig. 3). Thus, both extensional and compres-
if the development of the extensional structures seems to be syn- sional structures are simultaneously active, as highlighted by the
chronous along the entire rift (Dart et al., 1993). Seismic and deformation of the seafloor; seismic lines (e.g., CROP M24) ev-
gravimetric analysis of crustal structure indicates that the crust idence the coexistence of active normal and reverse faults (Fig.
has been tectonically thinned to less than 20 km in the Pantelle- 6). Interference between extension and compression generates
ria, Linosa, and Malta grabens with respect to the crustal thick- complex fault arrangements whose principal expression is a
ness of the Africa plate, ~30 km (Scarascia et al., 2000). The prominent curvature of the major thrust systems approaching
thickness of the crust increases toward the accretionary prism, the region affected by extension (Fig. 3).
where extensional structures, although still identifiable, are
clearly subordinated to thrust systems (Fig. 2). In the accre- SPACE GEODESY DATA ANALYSIS
tionary prism north of Pantelleria, bathymetric analysis shows
higher topography with respect to regions farther southeast, as The southern Italian GPS stations are included in the Euro-
crustal thickening related to the compressional process acts pean Reference Frame network, EUREF (see http://www
against reduction in topography induced by extension (Fig. 2). .euref-iag.org), where plate motions are reported with respect to
However, a northwest-southeast-directed depression propagates a fixed Europe. For our space geodesy analysis in the Sicily