Investigating the Relationship Between Seismological and Topological Properties of Seismicity in Italy and Taiwan

This study investigates the relationship between the b value of the Gutenberg–Richter law and the so-called k–M slope, a topological parameters, derived from the visibility graph analysis, that recently has been gaining great attention in describing the time dynamics of seismicity. The relationship has been already found to be nearly linear for several seismic areas. In this paper, we investigate such relationship in two of the most seismically active areas of the world: Italy and Taiwan. Our findings indicate that the relationship between the Gutenberg–Richter b value and k–M slope is nearly linear with a slope of regression line of about 0.07. Furthermore, analysing the seismicity by using the directed visibility graph, the role of the aftershocks is evidenced by the value of two new parameters, defined as the difference and the ratio between the forward directed and the backward directed k–M slopes, which are higher for the whole catalogues than for the aftershock-depleted ones.