The Mw=7.7 Tocopilla Earthquake (North Chile) of November 14, 2007: First results from space geodesy (InSAR)
| Autor: | Bejar Pizarro, Marta, Socquet, A., Armijo, R., Chabalier, J.B. de |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | E-Prints Complutense: Archivo Institucional de la UCM Universidad Complutense de Madrid E-Prints Complutense. Archivo Institucional de la UCM instname |
| Popis: | A Mw 7.7 subduction earthquake occurred on November 14, 2007 in Tocopilla (northern Chile). This region (between 16.5ºS and 23.5ºS) had been identified as major seismic gap (~1000 km length) since the South Peru (Mw= 9.1, 16 August 1868) and the Iquique (Mw=9.0, 10 May 1877) megathrust earthquakes. This gap was reduced to 500 km after the Arequipa (Mw = 8.3, 23 June 2001) and the Antofagasta (Mw = 8.1, 30 July 1995) earthquakes. We compute interferograms using Envisat ASAR images acquired before and after the Tocopilla earthquake to infer the location, geometry and slip of the rupture. Elastic modeling of this data allows us to infer that the 2007 main rupture extended over an area of ~150 x 60 km2, between 35 and 55 km depth, with a mean displacement of ~ 1.3 m. That means that the Tocopilla earthquake ruptured the deeper part of the seismogenic interface, probably within the transition zone. This earthquake released a little portion of the slip deficit accumulated in the seismic gap during the last 130 years (~ 10m). Hence the Tocopilla event may constitute a precursor of a future large thrust event in the current 500 km seismic gap that continues accumulating elastic strain from 1877. |
| Databáze: | OpenAIRE |
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