Temporal and spatial scaling properties of the aftershocks sequence of the 2023 Mw 6.8 Al Haouz earthquake (Morocco)

Abstract

On 8 September 2023, a strong seismic event measuring Mw = 6.8 struck the Western High Atlas Mountains of Morocco, causing extensive damage and resulting in over 2900 casualties. This earthquake initiated a series of aftershocks along the major faults in the Western High Atlas, with a total of 1917 events ranging from magnitudes 1–5.6 recorded during the first 30 days following the mainshock. To investigate the temporal and spatial dynamics of this sequence, we applied a set of nonlinear analysis tools: Rescaled Range Analysis, Allan Factor, Count-based Periodogram, and temporal/spatial correlation dimensions that are designed to detect scaling laws, long-range correlations, and fractal clustering in seismicity, features that cannot be fully captured by linear approaches. Utilizing the Gutenberg–Richter law, a b-value of 0.80 was determined for the aftershock sequence, which may suggest that the mainshock originated in a relatively high differential stress regime. Analysis of events above the completeness magnitude of 1.4 revealed strong time-clustering behavior and multi-scale fluctuations consistent with power-law statistics, indicating a fractal organization of the sequence. These results not only confirm the presence of memory effects and correlation structures in the Al Haouz aftershocks but also quantify their intensity through the scaling exponents, offering insights into rupture processes, fault geometries, and the underlying patterns of seismicity in the region.