DBPapers
DOI: 10.5593/sgem2017/14/S05.006

ASSESSING THE CRUSTAL MODELS AND GEODYNAMICS BEHAVIOR IN WESTERN PART OF ROMANIA

A. Bala, D. Toma-Danila, B. Grecu, D. Tataru
Monday 11 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-00-3 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 14, 41-48 pp, DOI: 10.5593/sgem2017/14/S05.006

ABSTRACT

First results about crustal models were obtained from various geophysical and seismological methods applied in Romania in the last part of XX century. A thorough interpretation of these data lead to the first partial models of crustal structure in the western part of Romania. In the first years after 2000 two regional seismic refraction lines were performed within a close cooperation with German partners from University of Karlsruhe. One of these lines is Vrancea 2001, with 420 km in length, almost half of the events being recorded in the Transylvanian Basin. The interpretation of this line give a first look at the crustal structure in central Romania based on seismic data recorded along the profile. The structure of the crust along the seismic line revealed a very complicated crustal structure beginning with Carpathians Orogen and continuing in the Transylvanian Basin. As a result of the development in the last ten years of the seismic network, some 100 permanent broadband stations are now continuously operating in Romania. The data gathered so far is valuable for seismicity and crustal structure studies, especially for the western part of the country, where this kind of data was sparse until now. Complementary to this national dataset, maintained and developed in the National Institute for Earth Physics, new data emerged from temporary networks established during the joint projects with European partners in the last decades. Between 2009 – 2011 a temporary network of 33 broadband seismic stations were deployed and autonomously operated in an area covering the western part of Romania. The results show a thin crust for stations located in the eastern part of Pannonian Basin (28-30 km). In the Apuseni Mountains the Moho discontinuity can be found between 31 to 33 km depth. The stations within the Southern Carpathians are characterized by deeper crustal depths of about 33-36 km. Three lines crossing the western part of Romania are developed with 2D models of the variation of the seismic velocity in depth and the position of Moho boundary. The Moho boundary coincide generally with the isoline of seismic transverse velocity in depth of about 3.80 km/s. In the last chapter of the paper, fault systems in the study region are presented, their regional peculiarities as they appear in the available studies, projected on the local tectonic structure for each of the areas under examination.

Keywords: crustal models, Moho discontinuity, geodynamic behavior