The system from south to north covers ten out of 32 departments of Colombia; Nariño, Putumayo, Cauca, Huila, Caquetá, Cundinamarca, Meta, Boyacá, Casanare and Arauca.

The Eastern Frontal Fault System underlies and affects the capitals of Putumayo, Mocoa, Caquetá, Florencia, Meta, Villavicencio and Casanare, Yopal.

The fault system forms the boundary between the North Andes microplate and the South American Plate.

The fault system developed from an initial set of parallel fractures (strike joints) arising from distensional forces.

The Guaicáramo Fault System deforms late Neogene deposits and is characterised by neotectonic morphology that is some of the most outstanding and continuous in the country.

North of the city of Yopal, it places Neogene rocks on the west against Quaternary alluvial deposits of the Llanos Basin on the east.

[6] The 156.5 kilometres (97.2 mi) long Algeciras Fault crosses the southward narrowing Eastern Ranges at an oblique angle, with its southern extension following the western flank.

Neotectonic deformation is suggested by the formation of a narrow and long pull-apart basin filled with Quaternary sediments.

[7] The 125.5 kilometres (78.0 mi) long Garzón-Pitalito Fault extends along the western slope of the Eastern Ranges southeast from the city of Neiva and crosses the upper part of the Magdalena Valley.

The place of the offset is marked by a large shutter ridge near where the Suaza River was dammed by huge landslides as a result of the earthquake of November 16, 1827.

[8] The 125.8 kilometres (78.2 mi) long Suaza Fault crosses the western slope of the Eastern Ranges, close to the Upper Magdalena Valley.

[9] The 117.1 kilometres (72.8 mi) long Mocoa Fault strikes close to the base of the eastern side of the mountain front of the central mountains and coincides with the abrupt change in slope between the Andean Range on the west and the dense forest-covered hilly lowlands on the east.

[12] Gómez Tapias, Jorge; Montes Ramírez, Nohora E.; Almanza Meléndez, María F.; Alcárcel Gutiérrez, Fernando A.; Madrid Montoya, César A.; Diederix, Hans (2015).