Title
Kinematic study of Iquique 2014 M<inf>w</inf> 8.1 earthquake: Understanding the segmentation of the seismogenic zone
Date Issued
01 December 2018
Access level
metadata only access
Resource Type
journal article
Author(s)
Jara J.
Sánchez-Reyes H.
Socquet A.
Cotton F.
Virieux J.
Maksymowicz A.
Díaz-Mojica J.
Walpersdorf A.
Ruiz J.
Cotte N.
Publisher(s)
Elsevier B.V.
Abstract
We study the rupture processes of Iquique earthquake Mw 8.1 (2014/04/01) and its largest aftershock Mw 7.7 (2014/04/03) that ruptured the North Chile subduction zone. High-rate Global Positioning System (GPS) recordings and strong motion data are used to reconstruct the evolution of the slip amplitude, rise time and rupture time of both earthquakes. A two-step inversion scheme is assumed, by first building prior models for both earthquakes from the inversion of the estimated static displacements and then, kinematic inversions in the frequency domain are carried out taken into account this prior information. The preferred model for the mainshock exhibits a seismic moment of 1.73 × 1021 Nm (Mw 8.1) and maximum slip of ∼9 m, while the aftershock model has a seismic moment of 3.88 × 1020 (Mw 7.7) and a maximum slip of ∼3 m. For both earthquakes, the final slip distributions show two asperities (a shallow one and a deep one) separated by an area with significant slip deficit. This suggests a segmentation along-dip which might be related to a change of the dipping angle of the subducting slab inferred from gravimetric data. Along-strike, the areas where the seismic ruptures stopped seem to be well correlated with geological features observed from geophysical information (high-resolution bathymetry, gravimetry and coupling maps) that are representative of the long-term segmentation of the subduction margin. Considering the spatially limited portions that were broken by these two earthquakes, our results support the idea that the seismic gap is not filled yet.
Start page
131
End page
143
Volume
503
Language
English
OCDE Knowledge area
Geología Sensores remotos Geoquímica, Geofísica
Scopus EID
2-s2.0-85054505841
Source
Earth and Planetary Science Letters
ISSN of the container
0012821X
Sponsor(s)
The authors thank the International Plate Boundary Observatory Chile (IPOC, www.ipoc-network.org ), Laboratoire International Associé “Montessus de Ballore” ( www.lia-mb.net ), Central Andean Tectonic Observatory Geodetic Array (CAnTO, http://www.tectonics.caltech.edu/resources/continuous_gps.html ), Instituto Geofísico del Perú ( www.igp.gob.pe ) and Centro Sismológico Nacional de Chile (CSN, www.csn.uchile.cl ) for making the raw GPS and strong motion data available. Jorge Jara acknowledges a Ph.D. scholarship granted by Chilean National Science Cooperation (CONICYT) through “Becas Chile” Program. Hugo Sanchez-Reyes thanks the Centre National de la Recherche Scientifique (CNRS) for a Ph.D. scholarship. This work has been supported by grants from Labex OSUG@2020 (Investissement d'avenir – ANR10 LAB56 ), IRD AO-Sud , and by ANR-17-CE31-0002-01 AtypicSSE . This work was partially supported by funding from the European Research Council ( ERC ) under the European Union's Horizon 2020 research and innovation program (grant agreement 758210 , project Geo4D). The authors would like to thank E. Contreras-Reyes, M. Radiguet, M. Causse, L. Audin, J. Pina-Valdes, R. Jolivet, H. Bhat, C. Vigny and M. Bouchon for all the constructive discussions about this work. Finally, the authors thank Z. Duputel, an anonymous reviewer, and the Editor J.P. Avouac for their constructive comments.
Sources of information: Directorio de Producción Científica Scopus