Geokinematics of Central Europe: New insights from the CERGOP-2/Environment Project

Abstract

The Central European Geodynamics Project CERGOP-2, funded by the European Union from 2003 to 2006 under the 5th Framework Programme, benefited from repeated measurements of the coordinates 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 available data up to 2005. The analysis has yielded velocities for some 60 sites, covering a variety of Central European tectonic provinces, from the Adria Indenter to the Tauern Window, the Dinarides, the Pannonian Basin, the Vrancea Seismic Zone and the Carpathian Mountains. The estimated velocities define kinematical patterns which outline, with varying spatial resolution depending on the station density and history, the present-day surface kinematics in Central Europe. Horizontal velocities are analyzed after removal from the ITRF2000 estimated velocities of a rigid rotation accounting for the mean motion of Europe: a ∼2.3 mm/year north-south oriented convergence rate between Adria and the Southern Alps that can be considered to be the present-day velocity of the Adria Indenter relative to the European Foreland. An eastward extrusion zone initiates at the Tauern Window. The lateral eastward flow towards the Pannonian Basin exhibits a gentle gradient from 1 to 1.5 mm/year immediately east of the Tauern Window to zero in the Pannonian Basin. This kinematic continuity implies that the Pannonian plate fragment recently suggested by seismic data does not require a specific Eulerian pole. On the southeastern boundary of the Adria microplate, we report a velocity drop from 4 to 4.5 mm/year motion near Matera to ∼1 mm/year north of the Dinarides, in the southwestern part of the Pannonian Basin. A positive velocity gradient as one moves south from West Ukraine across Rumania and Bulgaria is estimated to be 2 mm/year on a scale of 600-800 km, as if the crust were dragged by the counterclockwise rotation along

Persistent pre-seismic signature detected by means of Na-K-Mg geothermometry records in a saline spring of Vrancea area (Romania)

“…Since the immediate cause of the processes controlling the observed Na-K-Mg geothermometer fluctuations assumedly occurred in the shallow crust, at a depth of about 7-8 km at maximum (Mitrofan et al, 2008), a definite coupling should then exist between subcrustal and crustal deformations, related -in one way or another -to the generation of the Vrancea major earthquakes. This is in contrast with opinions expressed by most previous investigators, who, by taking into account the overall Vrancea seismicity pattern, appeared to be reticent in admitting that present-day deformation of the crust could be distinctively related to the subcrustal domain seismogenesis (see, for instance, Sperner et al, 2001;Gvirtzman, 2002;Van Der Hoeven et al, 2005;Heidbach et al, 2007;Radulian et al, 2007;Caporali et al, 2008).…”

Magnetotelluric Studies of Active Continent–Continent Collisions

“…Structural mapping and seismic reflection have been combined to image structures from outcrop to the upper mantle, and are dominated by South-dipping structures in the crust formed by underthrusting (Schmid et al 1996). Geodetic data show relatively slow rates of deformation across the Alps of the order of 2 mm per year (Caporali et al 2008), which is more than an order of magnitude less than for convergence across the Himalaya. It appears that the Alps are in a late stage of collision with gravitational collapse occurring in the West and horizontal extrusion continuing in the East (Selverstone 2005).…”

Observation of local tectonic movements by a quartz-tube extensometer in the Sopronbánfalva Geodynamic Observatory, in Hungary – Validation of extensometric data by tidal analysis and simultaneous radon concentration measurements

“…Measurements and data processing are carried out by different groups in close international co-operation, e.g. within the Central Europe Regional Geodynamics Projects CERGOP and CERGOP-2 (Grenerczy et al, 2000;Caporali et al, 2008). Grenerczy et al (2000) determined the strain rate from GPS data (from 1994 to 1998) of the CEGRN and the Hungarian GPS Geodynamic Reference Network in two regions (A and B in Fig.…”

“…6) and the direction of the principal contraction strain rate in the B section. These directions correspond to forces which move the East Alpine-North Pannonian unit to the east and rotate it clockwise (Bada et al, 2007a;Caporali et al, 2008). Results derived from a borehole breakout, earthquake focal mechanism (FMS) and overcoring measurements in the vicinity of the MM zone show diverse local maximum strain directions (Bada et al, 2007b).…”

“…Arrows denote the intraplate velocities inferred from GPS measurements. Velocities at the sites WTZR, HFLK, HUTB, GRAZ, PENZ, DISZ were determined by Caporali et al (2008); the velocity at the site SOPRON was determined by Grenerczy et al (2000). Double arrows denote the strain rates inferred from GPS observations.…”