The structure and contemporary activity of the Intramoesian fault in northeastern Bulgaria obtained through a complex of new geological-geophysical methods

Abstract

The structure of the Intramoesian fault is studied for the purpose of estimating its contemporary activity. The fault is known in the territory of Romania and Bulgaria, but it is insufficiently studied both from the geological point of view on the surface and from the geophysical point of view, from which the pattern of its deep structure can be inferred. The fault zone is the key structure for the solution of the problem of estimating the seismic hazard of the region, since the latest studies of this territory indicate the existence of traces of relatively young tectonic processes. According to some concepts the Intramoesian fault sets bounds to the tectonic plate, which is subducted under the Carpathian fold system in the region of the Vrancea Mountains. The paper under consideration presents the results of the field study of the southeastern, the Bulgarian, part of the fault with the application of a complex of geological-geomorphological and geophysical methods. On this basis, the structural segmentation of the fault is carried out and the specific features of its intersection with the disjunctives of another structural orientation are inferred. The data, which determine the degree of its geological and seismic activity, are also discussed.