Earthquake magnitude relationships in the region of the Carpathian-Pannonian Basin: Fid-Bau Portal

Earthquake magnitude relationships in the region of the Carpathian-Pannonian Basin

Zsíros, T.

Abstract In the region of the Carpathian-Pannonian Basin (44–50N; 13–28E) 81 earthquakes have moment magnitude (Mw); 61 of them are crustal events (focal depth <65 km) while 20 earthquakes belong to the intermediate focal depth region of the Vrancea (Romania) zone. For crustal events the regression of moment magnitude (Mw) on local magnitude (Ml) shows a better fit for large magnitudes using a second order equation against to a linear relationship, and the actual quadratic formula based on 61 events is the following: $$\matrix{{{M_w} = 1.37( \pm 0.28) + 0.39( \pm 0.18){M_l} + 0.061( \pm 0.026)M_l^2} \cr {({M_w}:1.9 - 5.5;{M_l}:1.4 - 5.5).}\cr}$$ In the intermediate focal depth Vrancea zone of the south-eastern bend of the Carpathians (44.5−46.5N; 25.5−28.0E) the number of body wave magnitudes is the largest one (20) among the local (8), the surface wave (14) and the duration (17) magnitudes. The linear relationship between the moment (Mw) and the body wave (Mb) magnitudes has the following form: $$\matrix{{{M_w} = 1.20( \pm 0.08){M_b} - 0.76( \pm 0.40)} \;\;\;\; {({M_w}:4.1 - 7.7;{M_b}:3.8 - 7.3).}\cr}$$ The relationships of the different (Ml, Ms, Mb, Md) magnitudes are also presented in the paper.