Subduction Zones and Related Volcanism in Northwestern South America

Abstract

The Eastern Equatorial Pacific is subject to spreading mechanisms from the ocean floor leading to subduction. A hotspot is observed to be the causeof the Galapagos Islands as well as other aseismic features on the segmented plates being subducted. A portion of the ocean crust has been obducted along the Colombia-and-Ecuador coast resulting in the Western Cordillera. Some ophiolite studies and rock sample measurements show agreement with marine refraction data. A synthetic seismic model contributes to know the oceanic crustal structure. Volcanic rocks in the northern part of the Andes are correlated with dipping of the Benioff zone showing agreement between the andesitic volcanism observed and subduction actually taking place in this complex area of northwestern South America