The present-day tectonic regimes of the Colombian Andes and the role of slab geometry in intraplate seismicity

2019 Mw 6.0 Mesetas (Colombia) Earthquake Sequence: Insights From Integrating Seismic and Morphostructural Observations

“…Therefore, it is likely that the southern part of the L‐pattern was triggered on the orthogonal fault system in the domino style, where minor faults with sinistral kinematics are located. The moment tensor and tectonic stress solutions show principal stress σ 1 of azimuth/plunge = 88°/4° (Figures 3d and 10c), this result is roughly in agreement with local transpressive stress regime in this area (Arcila & Muñoz–Martín, 2019; García‐Delgado et al., 2022). The occurrence of the Mesetas mainshocks on two closely spaced faults is explained in terms of the duplex style along a restraining bend zone and fit into the regional frame of transpressive tectonics (Figure 10a).…”

“…The Mesetas doublet is schematized by the interaction of two structural styles: duplex and domino, generated by transpressive regional tectonics where AFS is the main system. We also remark that the differences between the theoretical (Figure 10b) and mapped (Figure 10c) models are due to ancient fractures of the massif, reactivated during the latest Andean episode, under the present-day stress field (e.g., García-Delgado et al, 2022). Furthermore, the optimal orientation of faults (OOFs) is probably related to the orientation of the minor Riedels related to duplex and domino styles (Figure 10b).…”

“…Between 4°N and 7°N, the GPS results show primarily dextral strike‐slip in the Eastern Cordillera (Mora‐Páez et al., 2019). However, other pieces of evidence from focal mechanisms (Garcia‐Delgado et al., 2022) show local values of SHmax with orientations perpendicular to GFS between 5°N and 6°N. The geomorphic expression of AFS is characterized by several pull‐apart, rhomboidal shaped, and releasing sidestep basins (Diederix et al., 2021; Velandia et al., 2005).…”