TITLE:
Present Velocity Field in the Italian Region by GPS Data: Geodynamic/Tectonic Implications
AUTHORS:
Enzo Mantovani, Marcello Viti, Nicola Cenni, Daniele Babbucci, Caterina Tamburelli
KEYWORDS:
Geodesy, Geodynamics, Italy, Central Mediterranean
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.12,
December
29,
2015
ABSTRACT: The analysis of geodetic
observations carried out by 478 continuous GPS stations in the Italian region
since 2001 has allowed a fairly good definition of the ongoing horizontal
velocity field with respect to Eurasia. It is argued that such evidence can
provide important insights into the geodynamic context in the central
Mediterranean area. Numerous velocity vectors in the Apulia zone coherently
indicate that the southern Adriatic domain is moving roughly NE ward. Since no
significant decoupling zone between this domain and Nubia has so far been
recognized, one could expect that the kinematics of these two plates is
compatible. However, this condition is not fulfilled if the Nubia-Eurasia
relative motion is taken from the global kinematic models, either deduced by
long-term evidence[1]or short-term geodetic data[2][3]. This problem is considerably reduced
if the alternative Nubia-Eurasia rotation pole suggested by[4]is taken into account. This choice is also suggested by
other major long-term evidence in the Mediterranean region. The numerous
geodetic vectors available in two Adriatic sectors, the Apulia zone and the
Venetian plain, would imply an Adria-Eurasia rotation pole incompatible with
all Nubia-Eurasia Eulerian poles so far proposed. Since a significant relative
motion between these plates is not compatible with the absence of a tectonic
decoupling zone, we suppose that the short-term kinematics of Adria might be
influenced by a transient non-rigid behaviour of that plate. This hypothesis is
compatible with the expected effects (post seismic relaxation) of the major decoupling
earthquakes that have occurred along Periadriatic zones in the past tens of
years. The compatibility of the GPS kinematic pattern in the Apennine belt,
Calabria Arc and Sicily with the implications of the geodynamic/tectonic
interpretations so far proposed for the central Mediterranean area is then
discussed.