Title
Active tectonics of Peru: Heterogeneous interseismic coupling along the Nazca megathrust, rigid motion of the Peruvian Sliver, and Subandean shortening accommodation
Date Issued
01 October 2016
Access level
open access
Resource Type
journal article
Author(s)
Chlieh M.
Cavalié O.
Baby P.
Chire-Chira J.
Nocquet J.M.
Publisher(s)
Blackwell Publishing Ltd
Abstract
Over 100 GPS sites measured in 2008–2013 in Peru provide new insights into the present-day crustal deformation of the 2200 km long Peruvian margin. This margin is squeezed between the eastward subduction of the oceanic Nazca Plate at the South America trench axis and the westward continental subduction of the South American Plate beneath the Eastern Cordillera and Subandean orogenic wedge. Continental active faults and GPS data reveal the rigid motion of a Peruvian Forearc Sliver that extends from the oceanic trench axis to the Western-Eastern Cordilleras boundary and moves southeastward at 4–5 mm/yr relative to a stable South America reference frame. GPS data indicate that the Subandean shortening increases southward by 2 to 4 mm/yr. In a Peruvian Sliver reference frame, the residual GPS data indicate that the interseismic coupling along the Nazca megathrust is highly heterogeneous. Coupling in northern Peru is shallow and coincides with the site of previous moderate-sized and shallow tsunami-earthquakes. Deep coupling occurs in central and southern Peru, where repeated large and great megathrust earthquakes have occurred. The strong correlation between highly coupled areas and large ruptures suggests that seismic asperities are persistent features of the megathrust. Creeping segments appear at the extremities of great ruptures and where oceanic fracture zones and ridges enter the subduction zone, suggesting that these subducting structures play a major role in the seismic segmentation of the Peruvian margin. In central Peru, we estimate a recurrence time of 305 ± 40 years to reproduce the great 1746 Mw~8.8 Lima-Callao earthquake.
Start page
7371
End page
7394
Volume
121
Issue
10
Language
English
OCDE Knowledge area
Geografía física
Ingeniería ambiental y geológica
Vulcanología
Geología
Subjects
Scopus EID
2-s2.0-84992169542
Source
Journal of Geophysical Research: Solid Earth
ISSN of the container
21699313
Sponsor(s)
This work has been financially supported by the Agence Nationale de la Recherche (ANR; contract number ANR-07-BLAN-0143-01) and has been continuously supported by the Institut de Recherche pour le Développement (IRD) and the Instituto Geofísico del Perú (IGP). We thank all the people of the Instituto Geográfico Nacional, Lima, Peru, and Instituto Geográfico Militar, Quito, Ecuador, for their work in maintaining permanent GPS networks. We also thank all the colleagues from IGP and IRD that have been involved in this project. This work has been possible through the support provided by the IRD-DSF and the IGP to J.C.V.L. We acknowledge additional support from the CNRS-INSU and RESIF-CORE for the use of the GPS-national pool. This work has been carried out in the frame of the Joint International Laboratory “Seismes et Volcans dans les Andes du Nord.” The data used in this study are available in the supporting information. We used the GMT software [Wessel and Smith,] to prepare most of the figures. Finally, we thank L. Wallace, J. Loveless, and an anonymous reviewer for their comments and suggestions, which helped to improve this paper.
Sources of information:
Directorio de Producción Científica
Scopus