The Romeral Fault System (Spanish: Sistema de Fallas (de) Romeral) is a megaregional system of major parallel and anastomosing faults in the Central Ranges of the Colombian Andes and the Cauca, Amagá, and Sinú-San Jacinto Basins. The system spans across ten departments of Colombia, from northeast to south Bolívar, Sucre, Córdoba, Antioquia, Caldas, Risaralda, Quindío, Valle del Cauca, Cauca and Nariño. The fault zone extends into Ecuador where it is known as the Peltetec Fault System. The in detail described part of the Romeral Fault System south of Córdoba has a total length of 697.4 kilometres (433.3 mi) with a cumulative length of 1,787.9 kilometres (1,110.9 mi) and runs along an average north to south strike of 017.6 ± 16, cross-cutting the central-western portion of Colombia.
The fault system, active during more than 200 million years from the Triassic to recent, represents the ancient western continental margin of northwestern South America and forms the boundary between obducted oceanic crust to the west of the fault zone and continental crust to the east. The Romeral Fault System is situated at the intersection of five tectonic plates; the Caribbean Plate in the north, the Panama, Coiba and Malpelo Plates, formerly considered part of the Nazca Plate to the west and the North Andes Plate where the fault system is located. The Romeral Fault System forms the structural boundary between the Western and Central Ranges of the Colombian Andes. The tectonic depression produced by the fault zone in the central and southern portion is filled by the valley of the Cauca River, the second-most important fluvial artery of Colombia after the Magdalena River.
The major active volcanoes of Colombia, such as Galeras and Romeral are underlain by the Romeral Fault System. Segments of the fault zone are active, producing many minor and occasional devastating earthquakes, such as the 1983 earthquake in Popayán, Cauca and the 1999 Armenia earthquake, with a combined total of more than 2000 casualties. The capitals of Sucre (Sincelejo), Antioquia (Medellín), Caldas (Manizales), Quindío (Armenia), Risaralda (Pereira), Valle del Cauca (Cali), Cauca (Popayán) and Nariño (Pasto) are all situated near or on top of the fault zone.