Segmentation of the Nazca and South American plates along the Ecuador subduction zone from wide angle seismic profiles

Abstract : We describe the deep structure of the south Colombian-northern Ecuador convergent margin using travel time inversion of wide-angle seismic data recently collected offshore. The margin appears segmented into three contrasting zones. In the North Zone, affected by four great subduction earthquakes during the 20th century, normal oceanic crust subducts beneath the oceanic Cretaceous substratum of the margin underlined by seismic velocities as high as 6.0-6.5 km/s. In the Central Zone the subducting oceanic crust is over-thickened beneath the Carnegie Ridge. A steeper slope and a well-developed, high velocity, Cretaceous oceanic basement characterizes the margin wedge. This area coincides with a gap in significant subduction earthquake activity. In the South Zone, the subducting oceanic crust is normal. The fore-arc is characterized by large sedimentary basins suggesting significant subsidence. Velocities in the margin wedge are significantly lower and denote a different nature or a higher degree of fracturing. Even if the distance between the three profiles exceeds 150 km, the structural segmentation obtained along the Ecuadorian margin correlates well with the distribution of seismic activity and the neotectonic zonation.
Complete list of metadatas

https://hal.ird.fr/ird-00194762
Contributor : Anne-Sophie Archambeau <>
Submitted on : Friday, December 7, 2007 - 1:54:12 PM
Last modification on : Thursday, October 31, 2019 - 2:38:04 PM
Long-term archiving on: Monday, April 12, 2010 - 6:34:24 AM

File

Gailler_Charvis_Flueh_EPSL_200...
Files produced by the author(s)

Identifiers

Citation

A. Gailler, Philippe Charvis, E. R. Flueh. Segmentation of the Nazca and South American plates along the Ecuador subduction zone from wide angle seismic profiles. Earth and Planetary Science Letters, Elsevier, 2007, 260 (3-4), pp.444-464. ⟨10.1016/j.epsl.2007.05.045⟩. ⟨ird-00194762⟩

Share

Metrics

Record views

799

Files downloads

4423