Tectonics
Subduction of the Coiba plate underneath the North Andes plate causes frequent earthquakes in the Bucaramanga Nest, the most seismically active area in the world. The Bucaramanga-Santa Marta Fault stretches along the plate for more than 600 kilometers from north to south. The plate boundary with the South American plate is most tectonically active along a more than 900 kilometer long megaregional fault system; the Eastern Frontal Fault System.
This fault system, extending into Ecuador and Venezuela all along the northern Andes, separates the terranes from the North Andes plate from: [3]
South American plate features bordering the Chibcha terrane of the North Andes plate| Abbr | Name | Age range | Basins | Complexes | Ranges | Departments | Comments | Notes |
|---|
| PRNJ | Río Negro-Juruena Province | Paleoproterozoic | • Llanos
• Putumayo
• Amazonas | Mitú, Parguaza, Guaviare | Chiribiquete, Mavecure | Arauca, Caquetá, Casanare, Guainía, Guaviare, Meta, Putumayo, Vaupés, Vichada | Part of Amazonian Craton | [14] [15] |
|
The accreted terranes of the North Andes plate represent a complex geologic history. There have been two instances of intra-oceanic arcs colliding with the continent. The first of these events, which took place ~90-65Ma, involved the subduction of an intra-oceanic arc beneath the South American/North Andes plate. This subduction led to margin-parallel strike slip motion and shortening across the entire region. The second major collision occurred approximately 12Ma, during the Miocene. This event involved closing a ~1200 km-wide middle Eocene seaway and docking the Panama arc with South America. This second collision event also accelerated strike-slip faulting along the North Andes margin. Reconstruction studies of the area illustrate the complex dynamics of the tectonically active North Andes plate margin. [16]
Colombia 
Ecuador 
Venezuela 
