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Faure S.,University of Quebec at Montreal | Godey S.,European Mediterranean Seismological Center | Fallara F.,University of Quebec | Trepanier S.,University of Quebec at Montreal
Economic Geology | Year: 2011

The seismic architecture of the average Archean-only mantle beneath exposed and subsurface Archean crust of the United States and Canada is presented here in three dimensions for the first time, using a high lateral resolution Rayleigh wave phase velocity model of the upper mantle (30- to 250-km depth). The morphology of the cratonic coherent mantle is compared with other regional and local geophysical models, geologic interpretations, and published xenolith barometric studies. In particular, the kimberlite magma source regions at the Lithosphere-Asthenosphere Boundary (LAB) inferred from xenolith data are consistent with the bottom topography of the Archean seismic mantle signature. The characteristic fast seismic response found beneath much of the exposed Archean crust is also found in Canada beneath some covered terranes, sedimentary basins, and Proterozoic mobile belts. The northeastern and northwestern parts of the Superior craton host, with the central Hearne craton, the deepest mantle roots of North America (225- to 240-km depth). However, the southern portion of the Superior craton is characterized by an east-west channel that is 30 percent slower in seismic velocity than its northern counterpart. This contrasting seismic signature correlates with the location of the southernmost Neoarchean greenstone belts and to their plume-driven subduction zones. The scar in the mantle produced by this early tectonothermal event has been reused by widespread and sporadic carbonatite and kimberlite magmatic events spanning from the Early Proterozoic to the Cretaceous, and as a consequence, the diamond stability field has been partially to totally overprinted. Almost all diamondiferous kimberlites in Canada are located vertically over an interval of 160- to 200-km depth in areas of steep slopes surrounding deep (180-240 km), relatively small, and flat-bottomed Paleo-Mesoarchean cratonic keels. Source


Roca A.,Institute Geologic Of Catalonia | Gueguen P.,Joseph Fourier University | Godey S.,European Mediterranean Seismological Center | Goula X.,Institute Geologic Of Catalonia | And 6 more authors.
Geotechnical, Geological and Earthquake Engineering | Year: 2011

We created an archive for European acceleration data, based on distributed database of accelerogram waveforms, accessed through the new European Earthquake Data Portal (www.seismicportal.eu). Data are open to the scientific and engineering community. Currently the 6 core partners contribute data from 1,379 earthquakes with magnitudes ranging from M1.0 to M7.4. Strong Motion Data are available with epicentral distances up to 1,000 km. Additionally, agencies are encouraged to contribute data. Waveforms included in the database are uniformly processed to create a set of engineering parameters that are used to search the database. In addition to the database, we compiled a survey of the existing accelerometric stations in the Euro-Mediterranean region. We expect this platform to be the basis for growing sharing of European Strong Motion Data in an open environment, in as near to real-time as is possible from network operators. © Springer Science+Business Media B.V. 2011. Source


Pequegnat C.,Joseph Fourier University | Jacquot R.,Joseph Fourier University | Gueguen P.,Joseph Fourier University | Godey S.,European Mediterranean Seismological Center | Frobert L.,European Mediterranean Seismological Center
Geotechnical, Geological and Earthquake Engineering | Year: 2011

We developed a common access facility to homogeneously formatted accelerometric event data and to the corresponding sheet of ground motion parameters. This paper is focused on the description of the technical development of the accelerometric data server and the link with the accelerometric data explorer. The server is the third node of the 3-tier architecture of the distributed archive system for accelerometric data. The server is the link between the data users and the accelerometric data portal. The server follows three main steps: (1) Reading and analysis of the end-user request; (2) Processing and converting data; and (3) Archiving and updating the accelerometric data explorer. This paper presents the description of the data server and the data explorer for accessing data. © Springer Science+Business Media B.V. 2011. Source


Bossu R.,European Mediterranean Seismological Center | Gilles S.,European Mediterranean Seismological Center | Mazet-Roux G.,European Mediterranean Seismological Center | Roussel F.,European Mediterranean Seismological Center | And 2 more authors.
Annals of Geophysics | Year: 2011

This study presents the latest developments of an approach called 'flash sourcing', which provides information on the effects of an earthquake within minutes of its occurrence. Information is derived from an analysis of the website traffic surges of the European-Mediterranean Seismological Centre website after felt earthquakes. These surges are caused by eyewitnesses to a felt earthquake, who are the first who are informed of, and hence the first concerned by, an earthquake occurrence. Flash sourcing maps the felt area, and at least in some circumstances, the regions affected by severe damage or network disruption. We illustrate how the flash-sourced information improves and speeds up the delivery of public earthquake information, and beyond seismology, we consider what it can teach us about public responses when experiencing an earthquake. Future developments should improve the description of the earthquake effects and potentially contribute to the improvement of the efficiency of earthquake responses by filling the information gap after the occurrence of an earthquake. © 2011 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved. Source

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