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Seismicity of the Earth 1900-2013, seismotectonics of South America (Nazca Plate Region)

February 24, 2015

The South American arc extends over 7,000 kilometers (km), from the Chilean margin triple junction offshore of southern Chile, to its intersection with the Panama fracture zone, offshore of the southern coast of Panama in Central America. It marks the plate boundary between the subducting Nazca plate and the South America plate, where the oceanic crust and lithosphere of the Nazca plate begin their descent into the mantle beneath South America. The convergence associated with this subduction process is responsible for the uplift of the Andes Mountains, and for the active volcanic chain present along much of this deformation front. Relative to a fixed South America plate, the Nazca plate moves slightly north of eastwards at a rate varying from approximately 80 millimeters/year (mm/yr) in the south, to approximately 65 mm/yr in the north. Although the rate of subduction varies little along the entire arc, there are complex changes in the geologic processes along the subduction zone that dramatically influence volcanic activity, crustal deformation, earthquake generation and occurrence all along the western edge of South America.

Publication Year 2015
Title Seismicity of the Earth 1900-2013, seismotectonics of South America (Nazca Plate Region)
DOI 10.3133/ofr20151031E
Authors Gavin P. Hayes, Gregory M. Smoczyk, Harley M. Benz, Kevin P. Furlong, Antonio Villaseñor
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2015-1031
Index ID ofr20151031E
Record Source USGS Publications Warehouse
USGS Organization Geologic Hazards Science Center