The magnitude and rate of vertical movements have been
measured in the offshore Capo Vaticano (western Calabria) for
the Late Pleistocene - Holocene on the basis of the depth of
submerged coastal prism and associated wave-built terrace
formed during the sea-level lowstand of the Last Glacial
Maximum (LGM). Uplifted and submerged terraces have
proved to be valuable recorders of vertical motion in many
locations around the world (e.g. DICKINSON, 2001; WEBSTER et
alii, 2004) as the depth of their tops appear to be controlled by
the sea-level. In the eastern Tyrrhenian margins, depending on
the hydraulic energy conditions (i.e. waves and wind-induced
currents), the average water depth of terraced surface of
lowstand coastal prisms was probably 15-20 m (CHIOCCI &
ORLANDO, 1996).
A series of LGM lowstand coastal prisms and associated
wave-built terraces were identified on a new set of very highresolution
reflection seismic profiles acquired along the
continental shelf and upper slope of the western Calabria
continental margin. Data processing included time-depth
conversion and the interpretation of the resulting seismic lines
was performed using a GIS-based software package.
Seismic interpretation highlight that along the offshore
Capo Vaticano the slope-breaks associated with wave-built
terraced formed during the LGM deepens from ~130 m (cluster
A) to ~170 m (cluster B) below sea level (bsl) as one moves
from southwest to the northeast, over a distance of ~21 km
(Fig. 1). Farther to the north, along the western flank of the
Calabrian Arc, an average depth for the slope-breaks of ~165 m
is measured. Removal of the non tectonic component of vertical changes
using an ice-volume equivalent eustatic sea-level compilation
(LAMBECK et alii, 2011) indicates ~15 (± 5) m of uplift and
~25 (± 5) m of subsidence during the post-LGM for the
southern and northern sectors offshore Capo Vaticano,
respectively. The resulting average uplift and subsidence rates
(both regional and local components) for the last 20 (± 2) k.y.
are 0.75 (±0.325) mm/y and 1.25 (±0.375) mm/y, respectively.
The integration of the new data with those available in the
literature (e.g. TORTORICI et alii, 2003; CUCCI & TERTULLIANI,
2010; FERRANTI et alii, 2011) may provide information on
fault kinematics and constraints on slip rates of tectonic
structures that are relevant for earthquake hazard analysis of
western Calabrian margin.
REFERENCES
CHIOCCI, F. L. & ORLANDO L. (1996) - Lowstand terraces on
Tyrrhenian Sea steep continental scope. Marine Geology,
134, 127-143.
CUCCI, L. & TERTULLIANI A. (2010) - The Capo Vaticano
(Calabria) coastal terraces and the 1905 M7 earthquake:
the geomorphological signature of regional uplift and
coseismic slip in southern Italy. Terra Nova, 22, 378–389.
doi: 10.1111/j.1365-3121.2010.00961.x
DICKINSON, W.R. (2001)- Paleoshoreline record of relative
Holocene sea levels on Pacific islands. Earth-Science
Reviews, 55, p. 191–234. doi: 10.1016/S0012-8252
(01)00063-0.
FERRANTI L., SCICCHITANO G., SPAMPINATO C. R., ANTONIOLI
F., MONACO C. (2011) - Holocene coastal uplift at Capo
Vaticano, Calabria: implications for differential
deformation rates. Riassunti VIII Forum FIST Geoitalia
2011, 19-23 Settembre 2011, Torino. Epitome, 4, 153.
LAMBECK, K., F. ANTONIOLI, M. ANZIDEI, L. FERRANTI, G.
LEONI, G. SCICCHITANO & S. SILENZI (2011) - Sea level
change along the Italian coast during the Holocene and
projections for the future. Quaternary International, 232,
250-257.
WEBSTER, J.M., WALLACE, L., SILVER, E., APPLEGATE, B.,
POTTS, D., BRAGA, J.C., RIKER-COLEMAN, K. & GALLUP, C.
(2004) - Drowned carbonate platforms in the Huon Gulf,
Papua New Guinea. Geochemistry Geophysics
Geosystems, 5, p. Q11008, doi: 10.1029/2004GC000726.
TORTORICI, G., BIANCA, M., DE GUIDI, G., MONACO, C. &
TORTORICI, L. (2003) - Fault activity and marine terracing
in the Capo Vaticano area (southern Calabria) during the
Middle-Late Quaternary. Quatern. Int., 101–102, 269–27