Local magnitude is one of the oldest and widely used term for characterizing the size
of seismic events. Mostly based on the maximum amplitude measured on the components
of the seismograms associated with the seismic event. The events in the Hungarian
National Seismological Bulletin were relocated by Bondar et al. (2018). Before 2015
the bulletin did not contain amplitudes therefore it was not possible to calculate
new local magnitudes for the new hypocenters. Moreover, the magnitudes were calculated
by different methodology before 2015.
In this study, all three components of all available waveforms were collected for
the events occurred between 1996 and 2016, and the local magnitudes were recalculated.
Thus, we present a consistent data set for the whole period. Magnitude values based
on both horizontal and vertical components are presented.
Amplitudes were measured on all three components, thus it was possible to compare
the maximum amplitudes of the horizontal and vertical components recorded at stations
in different geological conditions. For stations located on sediment, generally higher
amplitude values were obtained on the horizontal components. The horizontal amplitude
was 2.5 or 3 times larger for the Great Hungarian Plain stations on thick sediments.
The differences between stations on firm bed rock were smaller.
The collected waveforms and amplitude measurements provide the opportunity to perform
the calibration of the local magnitude scale to the geological conditions of Hungary.
