Authors:Tivadar M. Tóth, É. Szűcs, Félix Schubert, and Cs. Hollós
Horváth, F., S. Cloething 1996: Stress-induced late-stage subsidence anomalies in the Pannonianbasin. - Tectonophysics, 266, pp. 287 - 300 .
Stress-induced late-stage subsidence anomalies in the Pannonianbasin
The crown architecture of the trees has only researched in the last decades. In this respect Hallé’s study is very important (Hallé et al. 1978), in this they described 23 architectural models about tropical tree species. This kind of model can not use for trees, which are in the temperate zone, therefore Pfisterer and Roloff (2010) worked out another architectural models. This present study gives a classification about the architectural models and types of native, frequently cultivated alien tree and shrub species in the Pannonian Basin. We classified the species into 8 architectural models, within it are 17 different architectural types. Three architectural models (Attims, Leeuwenberg, Scarrone) and 5 architectural types (Aesculus, Cryptomeria, Syringa, Thuja, Tsuga) only contain alien species.
We present the results of a fault reactivation study that used the analog modeling technique. The modeled tectonic processes represent the formation and subsequent deformation of the Derecske Trough and have implications for the evolution of the entire Pannonian basin system. Structural inversion of former thrusts led to normal faulting during the Miocene and corresponds to the formation, whereas subsequent reactivation of these faults in a strike-slip manner during the late Miocene to Quaternary represents neotectonic deformation of the basin. Modeling results show that reactivation of thrust faults in a transtensional manner can occur in a broad range of dip angles, and of angular differences between the maximum principal stress axis and the strike of the fault. The reactivation pattern of strike-slip zones in sandbox models critically depends on the orientation of the fault system with respect to the confining stress field, on the material property of the sand, and on the presence of a lubricant layer, representing a potential detachment horizon at the base of the models. The shear zones at the border zones of the Derecske pull-apart basin are prone to further reactivation, regarding the present-day stress field in the area. These inferences are confirmed by the recent seismic activity of the area, and point to the key importance of fault reactivation studies during seismic hazard assessment.
Tomographic P-wave velocity inversion has been performed for the Pannonian region using first arrival times of local and regional events from the bulletins of the International Seismological Center and the Hungarian Earthquake Bulletins. The input data consist of 4071 arrival times of 570 events. A three-dimensional velocity model has been gained by joint hypocenter-velocity inversion on a coarse and a fine non-uniform cartesian grid of nodes. The initial one-dimensional model was determined by genetic algorithm. A bending ray tracer has been used to calculate the theoretical travel times and ray paths. The reliability of the inverted velocity parameters were checked by the checkerboard method and by the analysis of the model resolution matrix. The results are generally in agreement with the known structural characteristics of the Pannonian Basin. An interesting high-velocity anomaly has been found in the uppermost mantle beneath the southern part of the Great Hungarian Plain.
Two effects have been studied concerning the former Wiese arrows and the newly determined complex induction vectors in the Pannonian backarc basin (Hungary): the remote effect of the curved Carpathian Conductivity Anomaly (CA) on the direction of the long period vectors, the local effect of the thickness (or conductance) of the conductive sediments on the induction vectors. The curvature of the Carpathian CA is clearly seen in the direction of the induction vectors as a remote effect dividing the Pannonian Basin into two great parts from this point of view. Following Zhang et al. (1993) who stated that the length (absolute value) of the induction vector becomes also constant in the “S-interval” as the magnetotelluric (MT) impedance which is related to the conductance of the sedimentary cover, it has been studied whether there is also any relation between the length of the induction vectors and the conductance of the same sedimentary cover (or thickness of sediment if its resistivity is constant). Due to the structural inhomogeneities to which the induction vectors are very sensitive, and to their great remote (side) effect, only a weak statistical relation has been found, nevertheless, its trend could be approximated by Ritter and Banks' (1998) theory. Exceptional cases are demonstrated.