Abstract

We present a fractality study performed in southern Norway (3 degrees - 12 degrees E, 57 degrees - 64 degrees N) using 12,892 low-magnitude intraplate seismic events. The earthquakes were recorded by the Norwegian National Seismic Network (NNSN) between the years 1980-2021. We calculated the multifractal spectrum dimension considering its temporal evolution and analyzing possible effects of the magnitude of completeness, M-c, on the results. We computed the multifractal spectrum dimension in data windows in order to follow the changes of the parameter D-q in time. The nonlinear behavior of this earthquake system has as an evidence how the temporal fractal dimension values vary approximately between D-q = 0.3 and D-q = 1.9 for 0 = q = 10 for different fractal windows. The capacity and correlation dimensions were equal to (D-0 ,D-2) =(2.06 +/- 0.06 , 1.72 +/- 0.05) and (D-0 ,D-2) =(2 . 13 +/- 0.001 ,D-2 = 1.70 +/- 0.05) for the catalog with and without Mc, respectively. The last suggests the existence of seismic sources related to linear fracturing and a slight seismic clustering, and confirms the effect of 2D seismogenic faults in the seismicity nucleation. As a novel contribution, we found a strong mathematical similarity between the fractal dimension D-10 and the earthquake magnitudes, which may be used as a new tool for earthquake forecasting in low-magnitude intraplate environments. We express this relationship through a linear equation valid for the South Norwegian intraplate seismicity. The results were, using the same procedure, compared with an intraplate seismic catalog from the Iquique area, located in northern Chile.