Evidence of active faulting obtained by the waveform inversion of the seismic moment tensor and InSAR analysis in Northeastern Mexico: El Corcovado seismic sequence of May to August 2023

Abstract

The first recorded moderate-intensity mainshock and largest aftershock in the boundary between the Basin and Range and Sierra Madre Oriental provinces are presented. This seismological evidence demonstrates the presence of active faulting in northeastern Mexico. We estimated seismic source parameters and surface deformation related to a low-moderate seismic sequence that occurred from May 11 to August 2, 2023 (3.4 ≤ M_d ≤ 5) in the limits of the San Luis Potosí, Nuevo León and Tamaulipas states through waveform inversion of the seismic moment tensor and InSAR analysis. The event of May 16, 2023 (M_d 5.0, M_w 4.92) is the biggest earthquake instrumentally recorded in this region. The mainshock and the largest aftershock (June 5, 2023; M_d 4.9, M_w 4.86) earthquakes were well-recorded over 100–330 km by broadband stations installed in central and northeastern Mexico. Here, it is suggested that both earthquakes were associated with the rupture of El Corcovado normal fault. We estimated a rupture area of approximately 11 km² with an average displacement of 7 cm. Fault plane solutions of the mainshock were strike 358°, dip 39°, rake −90°, and Mo 2.685e+16 Nm. El Corcovado fault is associated with a set of normal faults NNW-SSE trending located along the boundary between the Basin and Range and the Sierra Madre Oriental provinces. Such considerations lead to a review of the neotectonic setting of northeastern Mexico and the associated seismic hazard assessment.