hide
Free keywords:
-
Abstract:
In a seismically active region like Romania, an accurate and homogeneous determination of the seismic events’ magnitude is important for properly characterising events’ size and defining seismogenic areas. We present an automatic and reproducible scheme for local magnitude (ML) calculation based on the reviewed bulletins of the updated Romanian earthquakes catalogue (ROMPLUS) and the associated horizontal components of the station recordings. The applicability of the method is evaluated on three different case-studies, considered as typical examples, using earthquakes recorded between 2014 and 2023. Firstly, the magnitude calculation scheme is applied to anthropogenic and natural seismic events recorded in the North Romania regions, known for the quarries’ exploitations. Secondly, we analyse earthquakes from the Vrancea seismic region, mainly the events that occurred during the February 2023 Turkey-Syria damaging earthquake sequence, in order to review the magnitudes of the local events whose waveforms overlap with the surface waves generated by this sequence. Finally, the intense earthquake sequence from the Central Southern Carpathians seismic zone, with the main shocks corresponding to doublet earthquakes with magnitudes (ML) 5.2 and 5.7 and over 800 aftershocks, was analysed to evaluate the stability of the scheme.
We show that the proposed approach is able to provide a reliable automatic estimation of ML for seismic events, by minimising the magnitude error and allowing to select recordings with good signal-to-noise ratios. Our results demonstrate the usefulness of this scheme for the homogenisation of the ROMPLUS catalogue and its future extension to other seismically active areas of Romania.
