Macroseismic and seismotectonic analysis of the Mw 6.1 August 17, 2023 earthquake in the central region of Colombia
Análisis macrosísmico y sismotectónico del terremoto de magnitud Mw 6.1 ocurrido el 17 de agosto de 2023 en la región central de Colombia
Elkin de J. Salcedo-Hurtado1, *
, Augusto Antonio Gómez-Capera2, Carlos A. Vargas-Jiménez3, Germán Chicangana-Montón3,4, Héctor Mora-Páez5, Juan Miguel Velásquez6
1 Department of Geography, Universidad del Valle. Calle 100 #13-00, Comuna 17, Valle del Cauca, 760032, Cali, Colombia.
2 Sezione di Milano, Istituto Nazionale di Geofisica e Vulcanologia. Via Alfonso Corti 12, 20133, Milano, Italy.
3 Grupo Geofísica, Departamento de Geociencias, Universidad Nacional de Colombia, Bogotá.
4 Grupo Geoamenazas e Ingeniería Civil, Facultad de Ingeniería Civil, Universidad Santo Tomás, Villavicencio.
5 Facultad de Ciencias e Ingeniería, Universidad de Manizales. Cra. 9a #19-03, 170001 , Manizales, Caldas, Colombia.
6 Departamento de Matemáticas, Universidad del Valle. Calle 100 #13-00, Comuna 17, Valle del Cauca, 760032, Cali, Colombia.
* Corresponding author: (E. J. Salcedo-Hurtado) This email address is being protected from spambots. You need JavaScript enabled to view it.
How to cite this article:
Salcedo-Hurtado, E. J., Gómez-Capera, A. A., Vargas-Jiménez, C. A., Chicangana-Montón, G., Mora-Páez, H., & Velásquez, J. M. (2026). Macroseismic and seismotectonic analysis of the Mw 6.1 August 17, 2023 earthquake in the central region of Colombia. Boletín de la Sociedad Geológica Mexicana, 78(2), A281025. https://doi.org/10.18268/BSGM2026v78n2A281025
Manuscript received: August 1, 2025. Corrected manuscript received: October 14, 2025. Manuscript accepted: October 25, 2025.
ABSTRACT
This study conducts a complementary analysis of instrumental and macroseismic data regarding the August 17, 2023, earthquake in the central region of Colombia. This event is part of a historical earthquake sequence in the region, with an intensity higher than VII EMS-98, which has caused considerable material damage in the area. This earthquake had a magnitude of 6.1 Mw. The application of the attenuation model calibrated in magnitude Mw and the BW97 method allows for precise modeling of the location and magnitude from macroseismic data within an acceptable margin of uncertainty for both magnitudes (Mw±0.2) and location (±13 km). Using valid empirical regressions, we determine the parameters of the seismic focus size: horizontal extension L = 9.62 km, vertical extension lz = 15.76 km, rupture area A = 97.3 km2 , and deformed volume V = 1533.45 km3 . Within the first five days, at least 90 aftershocks were located by the Red Sismológica Nacional de Colombia (RSNC), supporting the source-area geometry inferred in this study. With these parameters and applying Kostrov’s model to the seismic flow of the rock mass, it was found that the maximum compressional strain rate is ε̇yy=1.22 x 10-6 yr-1, which is produced at an average velocity of 11.7 mm/ yr in the E-W direction.
Keywords: earthquake, aftershocks, focal mechanism, seismotectonic deformation, focus extension, Colombia.