## 5 Spatial Footprint of Coulomb Stress Changes
The green circles are the relocated hypocenters of the aftershocks which occurred after the Mw = 4.9 and before the major earthquake Mw = 6.0. The green lines show the surface projections of the two fault models. The focal mechanism of the mainshock was related to normal faulting and only a small portion of the strike-slip component was involved. A similar solution is evident for the largest foreshock (Mw4.9) and aftershock (Mw5.3) (Table 5) although, in the latter, the strike-slip component is increased. From the obtained co-seismic \(\Delta\)CFS changes we thus observe that most aftershocks, including those of greater magnitude, occurred within positive static stress changes produced by the major earthquake, and by the strongest aftershock. This suggests that the spatial distribution of aftershocks, including the significant ones, are controlled by the co-seismic Coulomb stress changes produced during the Mw = 6.0 mainshock and the major events of the sequence. Figure 13: **(Left)** Coulomb stress changes distribution due to Mw = 6.0 event (yellow star) at centroid depth of 10.0 km. The red rectangle indicates the fault model for the kinematics of Mw = 6.0, while the blue one is the projection of the fault model of Mw = 4.9 events (listed in Table 3). **(Right)** Coulomb stress changes along the vertical cross-sections A-B, C-D, E-F, and the parallel cross-section G-H (from up to down). The green circles are the relocated hypocenters of the aftershocks which occurred after the Mw = 6.0 main shock. The green lines show the surface projections of the two fault models. Frequency-Magnitude Scaling Properties of the Foreshock and Aftershock Sequences in Terms of Non-Extensive Statistical Physics  
The frequency-magnitude distribution (FMD), known as G-R law [56], is of vital importance for the characterization of a seismic sequence [56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69] and is expressed by Equation (4):  
\[logN=a-bM \tag{4}\]  
where \(N\) is either the discrete frequency of magnitudes \(M\) in each magnitude bin, or the cumulative frequency of magnitudes \(\geq\)\(M\); \(\alpha\), \(b\) are parameters determined by the earthquake catalog data, and the slope \(b\) of the G-R law expresses the relative number of the small magnitude earthquakes to the large magnitude ones and \(\alpha\) is a measure of the seismicity level. In terms of geophysics, the \(b\)-value is considered as a possible stress meter, e.g., [58]. In this context, low \(b\) indicates high material heterogeneity and concentrated stress while high \(b\) implies asymmetrically distributed stress. For details on the \(b\)-values for the Aracolchori seismic sequence see [21]. An alternative model that describes the frequency-size distribution of earthquakes from the first principles of non-extensive statistical physics (NESP) was introduced in [70]. This model is based on Tsallis Entropy, a generalization of the Boltzmann-Gibbs one [71] that offers a coherent theoretical framework for analyzing complex dynamical systems with fractal features and long-range correlations [72]. The approach introduced in [70] considers that the seismic energy \(E\) is related to the size of the fragments that fill the space between the activated fault blocks. Then, by considering that the earthquake magnitude is related to  
Figure 14: (**Left**) Coulomb stress changes distribution due to Mw = 5.4 major aftershock (yellow star) at centroid depth of 9.0 km. The red rectangle indicates the fault model for the kinematics of Mw = 5.4, while the blue ones are the projections of the fault models of Mw = 4.9 and Mw = 6.0 events (listed in Table 3). (**Right**) Coulomb stress changes along the cross-sections AB, CD. The green circles are the relocated hypocenters of the aftershocks which occurred after the Mw = 6.0 main shock. The green lines show the surface projections of the two fault models.