International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria)

Published: Oct 2015

Pages: 427 - 438

DOI: https://doi.org/10.1515/geoca-2015-0035

Authors: MILOŠ BRIESTENSKÝ, MATT D. ROWBERRY, JOSEF STEMBERK, PETAR STEFANOV, JOZEF VOZÁR, STANKA ŠEBELA, ĽUBOMÍR PETRO, PAVEL BELLA, ĽUDOVÍT GAAL, CHOLPONBEK ORMUKOV

Abstract: The EU-TecNet monitoring network uses customized three-dimensional extensometers to record transient de- formations across individual faults. This paper presents the first results from two newly established monitoring points in the Balkan Mountains in Bulgaria. The data from Saeva Dupka, recorded across an EEN-WWS striking fault, show sinis- tral strike-slip along the fault and subsidence of the southern block. Much of the subsidence occurred around the time of the distal MW= 5.6 Pernik Earthquake. An important transient deformation event, which began in autumn 2012, was reflected by significant compression and following extension, across the monitored fault. The data from Bacho Kiro, recorded across a NE—SW striking fault, show sinistral strike-slip along the fault and subsidence of the north-western block. The same important deformation event was reflected by changes in the strike-slip, dip-slip, and horizontal opening/closing trends. These results have been compared to data from other monitoring points in the Western Carpathians, External Dinarides, and Tian Shan. Many of the sites show evidence of simultaneous displacement anomalies and this observation is interpreted as a reflection of the plate-wide propagation of a tectonic pressure pulse towards the end of 2012.

Keywords: Eurasian Plate, Balkan Peninsula, active tectonics research, aseismic transient deformations, slow-slip phenomena, pressure pulse, EU-TecNet

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