Crustal motion along the Eurasia-Nubia plate boundary in the Calabrian Arc and Sicily and active extension in the Messina Straits from GPS measurements

We investigate crustal deformation along the Eurasia-Nubia plate boundary in
Calabria and Sicily revealed by the GPS velocity field obtained by the combination of
continuous site velocities with previous results from episodic campaigns. We recognize
two distinct crustal domains characterized by different motions and styles of deformation.
Convergence in Sicily is taken up by crustal shortening along the former Tyrrhenian back
arc passive margin, in agreement with seismological data and geological evidence of
recent cessation of deformation along the Plio-Pleistocene subduction front. The analysis
of the GPS data and the consistency between earthquake slip vectors and convergence
direction suggest that Eu-Nu convergence in Sicily does not require intermediate crustal
blocks. Significant Eurasia ( 3 mm/yr to NNE) and Nubia-fixed ( 5 mm/yr to ESE)
residual velocities in Calabria suggest instead the presence of an intermediate crustal block
which can be interpreted as a forearc sliver or as an independent Ionian block. According
to the first hypothesis, subduction is still active in the Ionian wedge, although we find
no evidence for active back arc spreading in the Tyrrhenian Sea. The N115 E oriented
Sicily-Calabria GPS relative motion is consistent with the extension observed during the
1908 Mw 7.1 Messina earthquake. We suggest that up to 3 mm/yr ( 80%) of this
estimated relative motion between Sicily and the Calabrian Arc may be taken up in the
Messina Straits.

References
Amoruso, A., L. Crescentini, and R. Scarpa (2002), Source parameters of
the 1908 Messina Straits, Italy, earthquake from geodetic and seismic
data, J. Geophys. Res., 107(B4), 2080, doi:10.1029/2001JB000434.
Anderson, H., and J. A. Jackson (1987), Active tectonics in the Adriatic
region, Geophys. J. R. Astron. Soc., 91, 937– 983.
Anzidei, M., P. Baldi, C. Bonini, G. Casula, S. Gandolfi, and F. Riguzzi
(1998), Geodetic surveys across the Messina Straits (southern Italy) seismogenetic
area, J. Geodyn., 25(2), 85–97.
Anzidei, M., P. Baldi, G. Casula, A. Galvani, E. Mantovani, A. Pesci,
F. Riguzzi, and E. Serpelloni (2001), Insights into present-day crustal
motion in the central Mediterranean area from GPS surveys, Geophys.
J. Int., 146, 98–110.
Argnani, A., et al. (2002), Tectonics of eastern Sicily offshore: Preliminary
results from the MESC 2001 marine seismic cruise, Boll. Geofis. Teor.
Appl., 43(3– 4), 177–193.
Argus, D. F., R. G. Gordon, C. DeMets, and S. Stein (1989), Closure of the
Africa-Eurasia-North American plate motion circuit and tectonics of the
Gloria fault, J. Geophys. Res., 94, 5585–5602.
Battaglia, M., M. H. Murray, E. Serpelloni, and R. Bu¨rgmann (2004),
The Adriatic region: An independent microplate within the Africa-
Eurasia collision zone, Geophys. Res. Lett., 31, L09605, doi:10.1029/
2004GL019723.
Bianca, M., C. Monaco, L. Tortorici, and L. Cernobori (1999), Quaternary
normal faulting in southeastern Sicily (Italy): A seismic source for the
1693 earthquake, Geophys. J. Int., 139, 370– 394.
Blewitt, G., and D. Lavalle´e (2002), Effect of annual signals on geodetic
velocity, J. Geophys. Res., 107(B7), 2145, doi:10.1029/2001JB000570.
Bonaccorso, A. (2002), Ground deformation of the southern sector of the
Aeolian Islands volcanic arc from geodetic data, Tectonophysics, 351,
181– 192.
Bordoni, P., and G. Valensise (1998), Deformation of the 125ka marine
terrace in Italy: Tectonic implications, in Coastal Tectonics, edited by I. S.
Stewart and C. Vita-Finzi, Geol. Soc. Spec. Publ., 146, 71– 110.
Boschi, E., D. Pantosti, and G. Valensise (1989), Modello di sorgente per il
terremoto di Messina del 1908 ed evoluzione recente dell’area dello
stretto, paper presented at Atti 89th GNDT Workshop, Cons. Naz. delle
Ric., Rome.
Boschi, E., G. Ferrari, P. Gasperini, E. Guidoboni, G. Smriglio, and
G. Valensise (1995), Catalogo Dei Forti Terremoti in Italia Dal 461
A. C. Al 1980, Ist. Naz. di Geofis., Rome.
Butler, R. W. H., M. Grasso, and F. La Manna (1992), Origin and deformation
of the Neogene-Recent Maghrebian foredeep at the Gela Nappe, SE
Sicily, J. Geol. Soc. London, 149, 547– 556.
Calais, E., J. M. Nocquet, F. Jouanne, and M. Tardy (2002), Current
extension in the central part of the Western Alps from continuous GPS
measurements, 1996– 2001, Geology, 30, 651– 654.
Calais, E., C. DeMets, and M. Nocquet (2003), Evidence for a post-3.16-Ma
change in Nubia-Eurasia-North America plate motions?, Earth Planet.
Sci. Lett., 216, 81– 92.
Catalano, R., C. Doglioni, and S. Merlini (2001), On the Mesozoic Ionian
Basin, Geophys. J. Int., 144, 49– 64.
Chiarabba, C., L. Jovane, and R. Di Stefano (2004), Instrumental seismicity
and seismotectonics of Italy, Tectonophysics, in press.
DeMets, C., R. G. Gordon, D. F. Argus, and S. Stein (1990), Current plate
motions, Geophys. J. Int., 101, 425– 478.
DeMets, C., R. G. Gordon, D. F. Argus, and S. Stein (1994), Effect of
recent revisions to the geomagnetic reversals time scale on estimates of
current plate motions, Geophys. Res. Lett., 21, 2191– 2194.
Dixon, T. H., M. Miller, F. Farina, H. Wang, and D. Johnson (2000),
Present-day motion of the Sierra Nevada block and some tectonic implications
for the Basin and Range province, North American Cordillera,
Tectonics, 19, 1 –24.
Doglioni, C., F. Innocenti, and G. Mariotti (2001), Why Mt Etna?, Terra
Nova, 13, 25–31.
Engdahl, E. R., R. van der Hilst, and R. Buland (1998), Global teleseismic
earthquake relocation with improved travel times and procedures for
depth determination, Bull. Seismol. Soc. Am., 88, 722– 743.
Faccenna, C., T. W. Becker, F. P. Lucente, L. Jolivet, and F. Rossetti
(2001a), History of subduction and back-arc extension in the central
Mediterranean, Geophys. J. Int., 145, 809–820.
Faccenna, C., F. Funiciello, D. Giardini, and F. P. Lucente (2001b), Episodic
back-arc extension during restricted mantle convection in the central
Mediterranean, Earth Planet. Sci. Lett., 87, 105–116.
Fernandes, R. M. S., B. A. C. Ambrosius, and R. Noomen (2003), The
relative motion between Africa and Eurasia as derived from ITRF2000
and GPS data, Geophys. Res. Lett., 30(16), 1828, doi:10.1029/
2003GL017089.
Frepoli, A., G. Selvaggi, C. Chiarabba, and A. Amato (1996), State of stress
in the Southern Tyrrhenian subduction zone from fault-plane solutions,
Geophys. J. Int., 125, 879– 891.
Galli, P., and V. Bosi (2002), Paleoseismology along the Cittanova fault:
Implications for seismotectonics and earthquake recurrence in Calabria
(southern Italy), J. Geophys. Res., 107(B3), 2044, doi:10.1029/
2001JB000234.
Galli, P., and V. Bosi (2003), Catastrophic 1638 earthquakes in Calabria
(southern Italy): New insights from paleoseismological investigation,
J. Geophys. Res., 108(B1), 2004, doi:10.1029/2001JB001713.
Gvirtzman, Z., and A. Nur (1999), The formation of Mount Etna as the
consequence of slab rollback, Nature, 401, 782–785.
Hollenstein, C. H., H.-G. Kahle, A. Geiger, S. Jenny, S. Goes, and
D. Giardini (2003), New GPS constraints on the Africa-Eurasia plate
boundary zone in southern Italy, Geophys. Res. Lett., 30(18), 1935,
doi:10.1029/2003GL017554.
Holt,W. E., and A. J. Haines (1993), Velocity fields in deforming Asia from
the inversion of earthquake-released strains, Tectonics, 12, 1 –20.
Hunstad, I., G. Selvaggi, N. D. Agostino, P. England, P. Clarke, and
M. Pierozzi (2003), Geodetic strain in peninsular Italy between 1875
and 2001, Geophys. Res. Lett., 30(4), 1181, doi:10.1029/2002GL016447.
Jacques, E., C. Monaco, P. Tapponnier, L. Tortorici, and T. Winter (2001),
Faulting amd earthquake triggering during the 1783 calabria seismic
sequence, Geophys. J. Int., 147, 499– 516.
Jarrard, R. D. (1986), Relations among subduction parameters, Rev.
Geophys., 24, 217– 284.
Lanzafame, G., and J. C. Bousquet (1997), The Maltese escarpment and its
extension from Mt. Etna to the Aeolian Islands (Sicily): Importance and
evolution of a lithosphere discontinuity, Acta Vulcanol., 9, 113– 120.
Malinverno, A., and W. B. Ryan (1986), Extension in the Tyrrhenian Sea
and shortening in the Apennines as arc migration driven by the sinking of
the lithosphere, Tectonics, 5, 227–245.
Mao, A., C. G. A. Harrison, and T. H. Dixon (1999), Noise in GPS
coordinate time series, J. Geophys. Res., 104, 2797– 2816.
Marani, M. P., and T. Trua (2002), Thermal constriction and slab tearing at
the origin of a superinflated spreading ridge: Marsili volcano (Tyrrhenian
Sea), J. Geophys. Res., 107(B9), 2188, doi:10.1029/2001JB000285.
Mazzuoli, R., L. Tortorici, and G. Ventura (1995), Oblique rifting in the
Aeolian Islands, Terra Nova, 7, 444–452.
McClusky, S., R. Reilinger, S. Mahmoud, D. Ben Sari, and A. Tealeb
(2003), GPS constraints on Africa (Nubia) and Arabia plate motions,
Geophys. J. Int., 155, 126– 138.
McKenzie, D. (1972), Active tectonics of the Mediterranean region,
Geophys. J. R. Astron. Soc., 30, 109– 185.
Monaco, C., L. Tortorici, R. Nicolich, L. Cernobori, and M. Costa (1996),
From collisional to rifted basins, an example from the southern Calabrian
Arc (Italy), Tectonophysics, 266, 233– 249.
Monaco, C., P. Tapponnier, L. Tortorici, and P. Y. Gillot (1997), Late
Quaternary slip rates on the Acireale-Piedimonte normal faults and tectonic
origin of Mt. Etna (Sicily), Earth Planet. Sci. Lett., 147, 125–139.
Montelli, , G. Nolet, F. A. Dahlen, G. Masters, E. R. Engdahl, and S. Hung
(2004), Finite-frequency tomography reveals a variety of plumes in the
mantle, Science, 303, 338–343.
Morel, J. L., and M. Meghraoui (1996), Goringe-Alboran-Tell tectonic
zone: A transpression system along the Africa-Eurasia plate boundary,
Geology, 24, 755– 758.
Nicolich, R., M. Laigle, A. Hirn, L. Cernobori, and J. Gallart (2000),
Crustal structure of the Ionian margin of Sicily: Etna volcano in the frame
of regional evolution, Tectonophysics, 329, 121– 139.
Oldow, J. S., L. Ferranti, D. S. Lewis, J. K. Campbell, B. D’Argenio,
R. Catalano, G. Pappone, L. Carmignani, P. Conti, and C. L. V. Aiken
(2002), Active fragmentation of Adria, the north African promontory,
central Mediterranean orogen, Geology, 30, 779– 782.
Patacca, E., R. Sartori, and P. Scandone (1990), Tyrrhenian basin and
Apenninic arcs. Kinematic relations since late Tortonian times, Mem.
Soc. Geol. Ital., 45, 425–451.
Pepe, F., G. Bertotti, F. Cella, and E. Marsella (2000), Rifted margin
formation in the south Tyrrhenian Sea: A high-resolution seismic
profile across the north Sicily passive continental margin, Tectonics,
19, 241– 257.
Piatanesi, A., and S. Tinti (1998), A revision of the 1693 eastern Sicily
earthquake and tsunami, J. Geophys. Res., 103, 2749–2758.
Pino, A. N., D. Giardini, and E. Boschi (2000), The December 28, 1908,
Messina Straits, southern Italy, earthquake: Waveform modeling of
regional seismograms, J. Geophys. Res., 105, 25,473– 25,492.
Pondrelli, S., C. Piromallo, and E. Serpelloni (2004), Convergence vs.
retreat in Southern Tyrrhenian Sea: Insights from kinematics, Geophys.
Res. Lett., 31, L06611, doi:10.1029/2003GL019223.
Sella, G., T. H. Dixon, and A. Mao (2002), REVEL: A model for Recent
plate velocities from space geodesy, J. Geophys. Res., 107(B4), 2081,
doi:10.1029/2000JB000033.
Selvaggi, G. (2001), Strain pattern of the Southern Tyrrhenian slab from
moment tensors of deep earthquakes: Implications on the down-dip
velocity, Ann. Geofis., 44(1), 155– 165.
Selvaggi, G., and C. Chiarabba (1995), Seismicity and P-wave velocity
image of the Southern Tyrrhenian subduction zone, Geophys. J. Int.,
121, 818– 826.
Shen, Z. K., D. D. Jackson, and B. X. Ge (1996), Crustal deformation
across and beyond the Los Angeles basin from geodetic measurements,
J. Geophys. Res., 101, 27,957– 27,980.
Tanguy, J. C., M. Condomines, and G. Kieffer (1997), Evolution of the
Mount Etna magma: constraints on the present feeding system and
eruptive mechanism, J. Volcanol. Geotherm. Res., 75, 221– 250.
Torelli, L., M. Grasso, G. Mazzoldi, and D. Peis (1998), Plio-Quaternary
tectonic evolution and structure of the Catania foredeep, the northern
Hyblean Plateau and the Ionian shelf (SE Sicily), Tectonophysics, 298,
209– 221.
Tortorici, L., C. Monaco, C. Tansi, and O. Cocina (1995), Recent and active
tectonics in the Calabrian Arc (southern Italy), Tectonophysics, 243, 37–
55.
Valensise, G., and D. Pantosti (1992), A 125 Kyr-long geological record of
seismic source repeatibility: The Messina Straits (southern Italy) and the
1908 earthquake (MS 7 1=2), Terra Nova, 4, 472–483.
Ward, S. N. (1994), Constraints on the seismotectonics of the central
Mediterranean from very long-base-line interferometry, Geophys. J. Int.,
117, 441– 452.
Westaway, R. (1990), Present-day kinematics of the plate boundary zone
between Africa and Europe, from the Azores to the Aegean, Earth
Planet. Sci. Lett., 96, 393– 406.
Zumberge, J. F., M. B. Heflin, D. C. Jefferson, M. M. Watkins, and J. F. H.
Webb (1997), Precise point positioning for the efficient and robust
analysis of GPS data from large networks, J. Geophys. Res., 102,
5005– 5017.