3 research outputs found
Geokinematics of Central Europe: New insights from the CERGOP-2/Environment Project
The Central European Geodynamics Project CERGOP/2, funded by the European Union from 2003to 2006 under the 5th Framework Programme, benefited from repeated measurements of thecoordinates of epoch and permanent GPS stations of the Central European GPS Reference Network(CEGRN), starting in 1994. Here we report on the results of the systematic processing of availabledata up to 2005. The analysis has yielded velocities for some 60 sites, covering a variety of CentralEuropean tectonic provinces, from the Adria indenter to the Tauern window, the Dinarides, thePannonian Basin, the Vrancea seismic zone and the Carpathian Mountains. The estimated velocitiesdefine kinematical patterns which outline, with varying spatial resolution depending on the stationdensity and history, the present day surface kinematics in Central Europe. Horizontal velocities areanalyzed after removal from the ITRF2000 estimated velocities of a rigid rotation accounting forthe mean motion of Europe: a ~2.3 mm/yr north-south oriented convergence rate between Adria andthe Southern Alps that can be considered to be the present day velocity of the Adria indenterrelative to the European foreland. An eastward extrusion zone initiates at the Tauern Window. Thelateral eastward flow towards the Pannonian Basin exhibits a gentle gradient from 1-1.5 mm/yrimmediately east of the Tauern Window to zero in the Pannonian Basin. This kinematic continuityimplies that the Pannonian plate fragment recently suggested by seismic data does not require aspecific Eulerian pole. On the southeastern boundary of the Adria microplate, we report a velocitydrop from 4-4.5 mm/yr motion near Matera to ~1 mm/yr north of the Dinarides, in the southwesternpart of the Pannonian Basin. A positive velocity gradient as one moves south from West Ukraineacross Rumania and Bulgaria is estimated to be 2 mm/yr on a scale of 600-800 km, as if the crustwere dragged by the counterclockwise rotation along the North Anatolian Fault Zone. This regimeapparently does not interfere with the Vrancea seismic zone: earthquakes there are sufficiently deep(> 100 km) that the brittle deformation at depth can be considered as decoupled from the creep atthe surface. We conclude that models of the Quaternary tectonics of Central and Eastern Europeshould not neglect the long wavelength, nearly aseismic deformation affecting the upper crust in theRomanian and Bulgarian regions
Surface kinematics in the Alpine-Carpathian-Dinaric and Balkan region inferred from a new multi-network GPS combination solution
The understanding of the intraplate tectonics of Central Europe requires a detailed picture of howstress is transferred
from the interaction of the Eurasian, Nubian and Anatolian plates to the Alpine, Carpathian, Pannonian and Dinaric
regions. Recent strain distribution is controlled by the Adria horizontal push, by the Vrancea vertical slab pull and
associated horizontal displacements, and by the Aegean/Anatolia extension and slab-roll back. We present a
horizontal velocity field for the Alpine-Carpathian-Pannonic-Dinaric and Balkan regions resulting from a new
combination of seven different GPS networks formed from permanent and campaign stations. Dedicated velocity
profiles in two specific regions are studied in detail. One is the Alpine Pannonian region,with a detailed picture of the
NS indentation of the Adriamicroplate into the Southern Alps, inNE Italy, the deformation in the Tauern Windowand
the eastwards kinematics of a Pannonian plate fragment. The second study region includes Transylvania, the Southern
Carpathians upto theAegean sea and Albania, where amajor right lateral shear deformation exists as a consequence of
theNE convergence of the Apulia platform towards the Dinarids, and theSSWmotion of Macedonia,Western Bulgaria
and Rumania, related to theHellenic arc dynamics in the EasternMediterranean. The profiles in the Alpine\u2013Pannonian
area indicate that a velocity drop of 2.5+/ 120.4 mm/yr associated with the Adria indentation concentrates on a
segment of some 50 kmsouth of the Periadriatic fault. The deformation becomes extensional by a similar amount just
north of the Periadriatic fault, in the Tauern Window, where the updoming of the Tauern Window implies vertical
motionwhich couldwell be associatedwith surface extension. In theEWprofile,we observe a sudden velocity change
of 1.5+/ 120.2 mm/yr in 20 km, corresponding to the right lateral Lavant fault, which seems to mark the border
between dominant indentation kinematics to theWest and dominant extrusion kinematics to the East.
Three profiles are considered in Southern and Eastern Europe: one across the lower Adriatic sea fromApulia in Italy to
the southern Dinarides, which enables it to constrain the velocity drop associated with the subduction of the Adria
microplate into the Dinarides to 3.2+/ 120.5 mm/yr in 140 km. The second profile is longitudinal and constrains the
velocity inversion of 7.4+/ 121.0 mm/yr in 350 km associated with right lateral shear faults in Albania. The third
profile crosses the Transylvania region with a shortening of 2.3+/ 121.0 mm/yr in 220 km, and the Wallachian\u2013
Moesian region up to the Chalcidic peninsula in NGreece. This lower part of the profile implies an extensional stretch
of the upper crust of 3.2+/ 120.9 mm/yr in 440 km, culminating in the Hellenic arc. Strain rate maps are presented in
this regional scale, showing the excellent agreement between fault plane solutions of crustal earthquakes and the eigenvectors of the GPS derived two dimensional strain rate tensor