Title:

Tectonic Setting, Historical Subduction Earthquakes, and the 10
August 2026 Mw 7.4 Earthquake in the Northern Colombian Andes

Abstract:

A strong Mw 7.4 earthquake struck Colombia on August 10, 2026. The earthquake was widely felt across the country, with a reported maximum peak ground acceleration (PGA) of approximately 500 cm/s². To date, 331 fatalities have been reported, together with widespread structural damage
across four major cities in the affected region. Approximately 36,226
buildings and dwellings were reported to have collapsed, including
hospitals and schools, while extensive damage to roads, airports, and other
critical infrastructure was also documented. In this talk, I will review
the tectonic setting of northwestern South America and the Caribbean
region, with particular emphasis on the complex geometry of the subducting
plates beneath the Northern Andes as revealed by seismic tomography
studies, and discuss its relationship to the occurrence of the 2026 Mw 7.4
Colombia earthquake. I will also present preliminary observations on the
source characteristics of the earthquake based on currently available
regional seismic data. Finally, I will summarize my previous work on the
source process of the 1906 Colombia–Ecuador earthquake, the largest
historical subduction megathrust earthquake known to have occurred in the
region, and discuss its relevance to this regional seismo-tectonic setting.