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Abstract:
The purpose of this study consists in the analyses of statistical parameters of seismicity, the released energy and the Coulomb stress change (deltaCFS) for the ongoing sequence started with a foreshock (Mw4.8) on 13.02.2023, followed by the main shock on 14.02.2023 (Mw5.4) in Romania, Targu Jiu area. The maximum macroseismic intensity reported in the area was VII MSK and PGA 0.15g. The seismic sequence (700+ events in less than one week) occurred at the contact between the Getic Depression, to the south, and the Southern Carpathians, to the north. The epicentral area is tectonically complex with various types of faults. The sequence may have activated normal faults, oriented WSW - ENE, as indicated by the focal mechanisms. Another sequence was recorded in the study area in 2012 (Radulian et al., 2014), with smaller earthquakes (maximum magnitude of 4.5), which occurred on reverse faults located south-east from the current sequence. The aftershocks will continue in the following months, but their number will decrease over time, according to the Omori law, which fits the preliminary data well. The seismic energy release will be computed using Mw resulted from the seismic moment (Mo). Aftershocks distribution and macroseismic maps will be used to improve fault characterization, which will facilitate the estimation of deltaCFS. We may tackle as well the debated question of a possible connection between the major earthquakes in Turkey on February 5 and 6 and the crustal earthquakes in Romania.This paper was financed by Nucleu PN23360201 SOL4RISC, and AFROS PN-III-P4-ID-PCE-2020-1361.