Fig. 9: A moment tensor and a focal mechanism are usually linked to each seismic event of large and moderate magnitude assuming the slip occurs on a planar fault.

If the fracture involves several faults, the DC contribution decreases producing a large CLVD term, which is then a good proxy for the complexity of faulting. However, the attribution of a single moment tensor may imply an underestimation of the seismic moment of the earthquake if the fault slip involves several fault patches with different orientations (a). The degree of complexity of the fault rupture can be simply characterized looking at the DC contribution of the moment tensor, which seems to differ as a function of the tectonic setting (b, data from ISC Catalogue) accordingly with the well-known positive correlation between the fractal dimension of the hypocentres time series and b-value (c, data from^{32, 65,66,67,68}, error bars from^{32, 65, 66}, estimated using the ranges of values in⁶⁷ assuming uniform distributions and computed from⁶⁸ following methods described in Section 4 and references therein).