A second triple junction occurs at the northwest corner of the plate where the Nazca, Cocos, and Pacific Plates all join off the coast of Colombia. Yet another triple junction occurs at the southwest corner at the intersection of the Nazca, Pacific, and Antarctic Plates off the coast of southern Chile. At each of these triple junctions an anomalous microplate exists, the Galapagos Microplate at the northern junction and the Juan Fernandez Microplate at the southern junction. The Easter Island Microplate is a third microplate that is located just north of the Juan Fernandez Microplate and lies just west of Easter Island.
The Carnegie Ridge is a 1,350-km-long and up to 300-km-wide feature on the ocean floor of the northern Nazca Plate that includes the Galápagos archipelago at its western end. It is being subducted under South America with the rest of the Nazca Plate.
The absolute motion of the Nazca Plate has been calibrated at 3.7 cm/yr east motion (88°), one of the fastest absolute motions of any tectonic plate. The subducting Nazca Plate, which exhibits unusual flat-slab subduction, is tearing as well as deforming as it is subducted (Barzangi and Isacks). The subduction has formed, and continues to form, the volcanicAndes Mountain Range. Deformation of the Nazca Plate even affects the geography of Bolivia, far to the east (Tinker et al.). It was on the Nazca Plate that the 1994 Bolivia earthquake occurred; this had a magnitude of 8.2 , which at that time was the strongest instrumentally recorded earthquake occurring deeper than 300 km.
Aside from the Juan Fernández Islands, this area has very few other islands that are affected by the earthquakes that are a result of complicated movements at these junctions.
Muawia Barazangi and Bryan L. Isacks, "Spatial distribution of earthquakes and subduction of the Nazca plate beneath South America" in Geology Vol. 4, No. 11, pp. 686–692. Abstract
Mark Andrew Tinker, Terry C. Wallace, Susan L. Beck, Stephen Myers, and Andrew Papanikolas, "Geometry and state of stress of the Nazca plate beneath Bolivia and its implication for the evolution of the Bolivian orocline" in Geology24(5), pp. 387–390 Abstract
Cahill, T. and B. Isacks (1992). "Seismicity and shape of the subducted Nazca plate." Journal Geophysical Research97 (12)
James, D. (1978). "Subduction of the Nazca plate beneath Central Peru." Geology6 (3) pp 174 – 178