Modeling Darcy-Type Pressure Pulses in the 2024–2025 Los Cabos Hydrometeorological-Seismic Event

Abstract During 2024–2025, an extended sequence of low-magnitude seismicity developed in the Los Cabos region, Baja California Sur, Mexico, exhibiting swarm-like behavior. The sequence occurred in a hyper-arid to arid climatic setting, where hydrometeorological forcing is typically limited. A single intense rainfall episode in September 2024 provided a well-constrained hydrological impulse perturbation, and we examine the spatiotemporal response of seismicity to transient pore-pressure disturbances. Later, a cluster of seismic events appeared within a confined region, namely El Tule, with progressive depth migration over a period of approximately 20 days. The resulting distance–time evolution is analyzed within a diffusion-based framework, interpreting the observed migration as a Darcy-type pressure pulse through a hydraulically connected crustal medium. An effective hydraulic diffusivity of approximately 1−2 m2/s is inferred from the seismicity envelope, consistent with values reported for fluid-influenced seismic sequences in fractured crust. We complement the analytical diffusion analysis with finite-element simulations of transient groundwater flow under simplified but geologically motivated structural configurations. The numerical results demonstrate that pressure perturbations initiated at the surface can propagate to seismogenic depths on timescales comparable to those inferred from the seismic observations, provided realistic contrasts in hydraulic properties are present within the crustal system. Although the observed diffusion-like migration and elevated b values provide strong evidence for fluid involvement, our results also demonstrate that Darcy-type pressure diffusion alone does not uniquely diagnose hydrometeorological triggering.