The 2016 January 25 earthquake (M w 6.3) follows in sequence from the1994 May 26 earthquake (M w 6.0) and the 2004 February 24 earthquake (M w 6.4) in the Rif Mountains and Alboran Sea. The earlier two seismic events which were destructive took place on inland conjugate faults, and the third event occurred on an offshore fault. These earthquake sequences occurred within a period of 22 yr at ∼25 km distance and 11-16-km depth. The three events have similar strike-slip focal mechanism solutions with NNE-SSW trending left-lateral faulting for the 1994 and 2016 events and NW-SE trending right-lateral faulting for the 2004 event. This shallow seismic sequence offers the possibility (i) to model the change in Coulomb Failure Function (CFF with low μ including the pore pressure change) and understand fault-rupture interaction, and (ii) to analyse the effect of pore fluid on the rupture mechanism, and infer the clock-time advance. The variation of static stress change has a direct impact on the main shock, aftershocks and related positive lobes of the 2004 earthquake rupture with a stress change increase of 0.7-1.1 bar. Similarly, the 2004 main shock and aftershocks indicate loading zones with a stress change (>0.25 bar) that includes the 2016 earthquake rupture. The tectonic loading of 19-24 nanostrain yr −1 obtained from the seismicity catalogue of Morocco is comparable to the 5.0 × 10 17 N•m yr −1 seismic strain release in the Rif Mountains. The seismic sequence is apparently controlled by the poroelastic properties of the seismogenic layer that depend on the undrained and drained fluid conditions. The short interseismic period between main shocks and higher rate of aftershocks with relatively large magnitudes (4 < M w < 5.5) implies the pore-fluid physical effect in undrained and drained conditions. The stress-rate ranges between 461 and 582 Pa yr −1 with a CFF of 0.2-1.1 bar. The computed clock-time advance reaches 239 ± 22 yr in agreement with the ∼10 yr delay between main shocks. The calculated static stress change of 0.9-1.3 bar, under pore-fluid stimulus added with well-constrained geodetic and seismic strain rates are critical for any seismic hazard assessment.

On 15 May 2020 at 11:03 (UTC) a shallow earthquake with a Magnitude Mw 6.5 struck the Central Walker Lane in the Mina Deflection region. This shallow event offers the possibility to model the change in Coulomb failure function (ΔCFF) including the historical events and to analyze the effect of fluid redistribution on fault ruptures. The static stress change modeling shows that the 1932 Cedar Mountain (Mw 7.1) earthquake increased ΔCFF on the 2020 Monte Cristo left‐lateral rupture by an average value of ∼2 bar suggesting a fault interaction in the context of conjugate strike‐slip faults. Also, the ΔCFF caused by the Monte Cristo earthquake shows a 0.1–0.5 bar increase on nearby right‐lateral fault planes at 8 km depth. In contrast to the 2019 Ridgecrest sequence (Mw 6.4 and Mw 7.1), our poroelastic stress change modeling of the 2020 Monte Cristo earthquake shows no apparent correlation between the positive stress change values and fluid redistribution along the Monte Cristo conjugated ruptures. Nevertheless, the Coulomb modeling using adapted poroelastic solutions shows that the 2020 Monte Cristo mainshock increased stresses with a value of 0.2–0.9 bar south of the Mina Deflection along the White Mountains and Fish Lake Valley fault zones. The stress values combined with a strain rate of 40–50 nanostrain/yr represent a shift of 8%–15% of the recurrence time interval for a large earthquake along the White Mountains and Fish Lake Valley faults suggesting an elevated pore‐fluid effect for faults reactivation in both undrained and drained fluid conditions.

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