Author(s)

Fida Medina¹, Taj-Eddine Cherkaoui²

¹Moroccan Association of Geosciences, Rabat, Morocco.
²Mohammed V University in Rabat, Rabat, Morocco.

We expose the results of the study of the south-western Alboran seismic sequence of January-March 2016 and the stress perturbations it caused by means of Coulomb modeling. The use of data from numerous stations allowed us to relocate the largest events (Mw ≥ 3.8) south of those determined by IGN (Spain). The main shock of 25 January 2016 (Mw = 6.3) was relocated at 35.6133°N × 3.6888°W, at a hypocentral depth of 15.5 ± 6.0 km. The epicenters are aligned along two distinct clusters: The first runs N-S towards the Moroccan coast along Al-Idrissi fracture zone, while the second is centered on the Alboran ridge northern thrust fault. The focal mechanisms determined by different agencies correspond to a strike-slip/normal/reverse motion in the western cluster and thrusting in the eastern one. Coulomb stress change modeling shows that the main earthquake: (1) may have been triggered by stress accumulation by the 1994 and 2004 earthquakes; (2) has induced stress perturbations that provide a suitable explanation for the distribution of the aftershock clusters, including the eastern cluster. The prediction of the next event shows that it is likely to occur near the Moroccan coast.

Morocco, Seismicity, Alboran, Al Hoceima, Coulomb Stress Change, Seismotectonics, Seismic Hazard

Medina, F. and Cherkaoui, T. (2017) The South-Western Alboran Earthquake Sequence of January-March 2016 and Its Associated Coulomb Stress Changes. Open Journal of Earthquake Research, 6, 35-54. doi: 10.4236/ojer.2017.61002.