Abstract
The b-value of the Gutenberg-Richter law, which describes the magnitude-frequency relationship of seismicity, is the most widely investigated statistical parameters derived from the study of earthquake catalogs. It serves as a proxy for properties of seismicity and it is fundamental for the probabilistic seismic hazard assessment. Recently, the application of the visibility graph (VG) method has experienced an increasing interest for analyzing various geophysical observables, including earthquake catalogs. This study uses the VG method to analyze six earthquake catalogs that span a wide range of scales, in terms of number of events, maximum magnitude, earthquake frequency rate, and types of seismicity. The results show a linear correlation between the VG connectivity degree (k) and earthquake magnitude (M), with the slope of this relationship being proportional to the b-value of the Gutenberg-Richter law. When combined with analogous data collected from the literature, these findings support the universal nature of this relation. The proposed scaling relationship could serve as a valuable tool for verifying and complementing the b-value in statistical seismology.