SEISMOGENIC ZONES IN THE EASTERN ALPINE-WESTERN CARPATHIAN-PANNONIAN JUNCTION AREA

The newly-defined seismo genic tones in the Alpine-Carpathian-pannonia n (ALCAPA) junction area are correlated with: (1) Paleoalpine deep-sea ted suture zones, either oceanic or intracontinental, (2) Neoalpine wr ench-fault zones following some sutures, and (3) original thrust plane s reactivated as low-angle extensional normal faults. 1-The principal West-Carpathian Paleoalpine sutures, from north to south, are: the Pen ninic-Vahic oceanic suture originated during the Late Cretaceous, the Certovica intracontinental suture between the Tatric and Veporic thick -skinned sheets locked some 90 Ma ago, and the Meliatic oceanic suture formed in the Late Jurassic, closely related to the Igal-Bukk Zone. T hese suture zones were partly reactivated during the Late Tertiary and represent weakened zones in the modern upper crust. The concentration of important earthquake epicenters correlates well with these weakene d belts which serves as a base for the new seismogenic model of the ar ea. 2-The most important wrench fault zone is situated between the Eas tern Alps and Western Carpathians. It reflects the Miocene extrusion o f the ALCAPA lithospheric fragment from the Alpine domain as its north western boundary. The NE-SW trending wrench fault zone is represented by the Mur-Murz-Leitha and Povazie fault systems. The zone is well exp ressed by flower structures in many seismic lines. 3-The Miocene back- are extension driven by the subduction pull in front of the Carpathian orogen and mantle updoming in the Pannonian domain reactivated origin al Paleoalpine thrusts as crustal detachment planes. In the Danube Bas in area, these are accompanied by numerous important faults visible in seismic sections, e.g. the Repce, Raba, Sladkovicovo and Mojmirovce f ault systems. The extension regime consequences of the core-mountains uplift during isostatic inversion from the Pliocene are visible in sei smic section 2T - along the Certovica Zone as strong reflector branche s. They represent former suture rejuvenated into younger low angle nor mal faults.