UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2022 Meeting


Section: Atmosphere and Earth Science; Environment Protection


Title:
A reanalysis of the ROMPLUS seismic events located in the northeast of Romania


Authors:
Iulia ARMEANU (1,2), Felix BORLEANU (2), Lavinia VARZARU (2), Daniela GHICA (2), Mihaela POPA (2,3)


Affiliation:
1) University of Bucharest, Faculty of Physics, 405 Atomistilor Street, 077125, Magurele, Romania

2) National Institute for Earth Physics, Magurele, Romania

3) Academy of Romanian Scientists, Bucharest, Romania



E-mail
iulia.armeanu@infp.ro


Keywords:
ROMPLUS catalogue, seismic events, statistical discrimination, waveforms cross-correlation, earthquakes relocation


Abstract:
In this study, we reanalyse seismic events recorded between 2005 and 2021 in the updated Romanian seismic catalogue (ROMPLUS) and located in the north-eastern part of Romania i.e., Bucovina region. As several quarries are currently active in this region, two types of sources, tectonic and anthropogenic, are mixed in ROMPLUS catalogue, causing errors when estimating the seismicity. Multiple methods were taken into account to achieve the objective of this research. The statistical methods were firstly applied, indicating the presence of anthropogenic events in the ROMPLUS catalogue for the Bucovina region. To increase the accuracy of the preceding analysis the waveforms cross-correlation technique was applied on the vertical seismograms recorded by BUR31, the broadband station of the Bucovina (BURAR) seismic array. Moreover, three events that showed significant depth errors were relocated by reviewing the onsets of the seismic phases and applying the LOCSAT algorithm embedded in the Antelope software environment. The events were relocated based on a 1-D velocity model which is commonly used to determine the earthquakes parameters reported in the catalogue. The results emphasize that proposed discrimination techniques are able to distinguish between tectonic and anthropogenic events. In addition, three seismic sequences and a swarm of earthquakes were identified in 2011, 2013 and 2017, delimiting two active seismic areas in Bucovina. The present analysis could be extended to other areas to enhance the data in the ROMPLUS catalogue contributing significantly to the future seismicity and seismic hazard studies.