New approaches in the seismotectonics of the marginal Dacides Unit

Abstract

The goal of this study is to perform a cross-correlation analysis of the earthquake sequences, recorded between 2014 and 2016 in the Caransebeș-Mehadia Area (CMA), in Romania, and to correlate the results with the surface geology, for a better understanding of the neotectonics processes taking place in the South-Western Carpathian Bend Zone. The apparent sparse seismicity between 1886 and 2005 in CMA is mostly due to the lack of seismic stations in the region before 2006. The image changed with 2006, when the recorded event rate increased to 3-15 events/year between 2006-2013 and 2017-2023 and to 45-70 events/year between 2014–2016-time intervals. The high number of events recorded between 2014 and 2016 is related to the occurrence of the three seismic sequences in the CMA: between 31/10/2014 and 20/02/2015, between 23/11/2015 and 28/12/2015 and between 27/07/2016 and 29/08/016. We apply the cross correlation analysis technique for the events recorded in the 2014-2016 time period to identify events belonging to a cluster and to identify new events undetected by routine seismic analysis. The templates used for the analysis were selected from the events recorded in ROMPLUS. We consider an event as belonging to a cluster if the cross-correlation coefficient is equal to or greater than 0.7. Four templates were used and the results show a detection of 37 new events belonging to the seismic sequences from CMA. The distribution of the epicentres shows a migration from west to east suggesting a possible post-triggering effect after the 2014 mainshock.