par, - 15 novembre 2013 ( dernière mise à jour : 4 avril 2016 )
Subject : Transient behavior and role of barriers in the North Chile – South Peru seismic gap
Supervisors : Anne Socquet
Fundings : CONICYT
Recent earthquakes in Japan and Chile (2011, 2010) have highlighted the need to address the seismic hazard in subduction seismic gaps not only based on seismological information, but also on other type of information, such as the interseismic coupling derived from geodetic data. In particular, determining the lateral variations of coupling allows to identify coupled zones that should rebound into a future earthquake, and creeping zones that may act as barriers to the propagation of earthquakes, that often correlate with topographic anomalies in the upper plate.
The objective of this PhD thesis is to better understand the behavior of these barriers during the seismic cycle. In particular, one aim is to investigate the potential role of geometrical complexities in the variation of the megathrust’s frictional behavior and in the genesis of permanent, volumetric deformation. Indeed these are critical issues to assess what controls the propagation or arrest of the seismic ruptures, and what controls the segmentation of subduction zones.
These investigations will be conducted in the Central Andes subduction zone (North Chile – South Peru), where no large megathrust earthquake (Mw>8.5) occurred since the 19th century. This seismic gap is the locus of a series of GPS measurements ( 40 cGPS stations) performed by French, Chilean, Peruvian and American teams (Franco Chilean International Lab. “Montessus de Ballore” between CNRS and U. de Chile, ISTerre-IRD, IGP Lima and Caltech).
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