Active tectonics of Peru

Active tectonics of Peru: Heterogeneous interseismic coupling along the Nazca megathrust, rigid motion of the Peruvian Sliver, and Subandean shortening accommodation

J. C. Villegas-Lanza1,2, M. Chlieh2, O. Cavalié2, H. Tavera1, P. Baby3, J. Chire-Chira4, and J.-M. Nocquet2

1Instituto Geofísico del Perú, Lima, Peru, 2Géoazur, IRD, Université de Nice Sophia-Antipolis, Observatoire de la Côte d’Azur,CNRS, Valbonne, France, 3Géosciences Environnement Toulouse, Université Paul Sabatier, IRD, CNRS, OMP, Toulouse,France, 4Instituto Geográfico Nacional, Lima, Peru

Correspondence to:

J. C. Villegas-Lanza,
Esta dirección electrónica esta protegida contra spam bots. Necesita activar JavaScript para visualizarla

Key Points:

• New GPS data provide insights on the present-day crustal deformation of the Peruvian Andes
• We describe the kinematics and boundaries of the Peruvian Forearc Sliver and Subandean retro-shortening rates
• We map a highly heterogeneous interseismic coupling pattern of the Nazca megathrust at the scale of the 2200 km of the Peruvian margin

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.

*click here to read this paper.


Primer Taller de Trabajo Low-Latitude Ionospheric Sensor Network



El taller tiene la finalidad de instruir a científicos, ingenieros y estudiantes de América del Sur en como emplear receptores de GPS y magnetómetros, para diagnosticar el estado y variabilidad de la ionósfera de bajas latitudes, e instruir en el procedimiento de como instalar y operar el estado...




» Magnetómetro LISN en Argentina

» LISN en la búsqueda de formar un observatorio distribuido
Acerca de LISN      |      Equipos      |      Información técnica y científica      |      Estaciones      |      Datos      |      Miscelánea      |      Descargas      |      Contacto
Copyright © 2017 Low-latitude Ionospheric Sensor Network    |    Radio Observatorio de Jicamarca     |     Instituto Geofísico del Perú