Seismological Research Letters; July/August 2008; v. 79; no. 4;
p. 498-503; DOI: 10.1785/gssrl.79.4.498
© 2008 Seismological Society of America
Cavascope: The Broadband Seismological Network of the New Hebrides Subduction Zone and Its Associated Data Base
Robert Pillet1
Pierre Lebellegard1,2,
Esline Garaebiti3, and
Daniel Rouland4
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INTRODUCTION
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Beginning in 1993, a seismological broadband network (named the Cavascope
network) was set up in New Caledonia and Vanuatu in the Southwest Pacific,
within a collaborative framework of researchers from the Institut de Recherche
pour le Développement, Nouméa, New Caledonia (IRD); Ecole et
Observatoire des Sciences de la Terre, Strasbourg, France (EOST); and the
Department of Geology, Mines and Water Resources of Vanuatu (DGMWR). This
seismological network, located in a particularly fast converging area,
i.e., the New Hebrides subduction zone, and surrounded by numerous
other very active seismic zones (Papua New Guinea, Salomon Islands, Fiji,
Tonga-Kermadec, and New Zealand) is of great interest to the scientific
community. In this article, we give a short overview of the tectonic setting
of the region and past seismological surveys, and then we present the
instrumental characteristics of the Cavascope network and its associated
database.
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THE NEW HEBRIDES TRENCH AND FORMER SEISMOLOGICAL SURVEY
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The active margin of New Hebrides is associated with the subduction of the
Australian plate under the North Fiji Basin. This extends 1,500 km from the
Santa Cruz archipelago in the north up to 23 degrees south, including the
entire Vanuatu archipelago (figure
1). This seismic zone is dipping with an angle of 60–70°
down to a depth of 300 km. The plate convergence axis trends ENE,
perpendicular to the trench, and the convergence rate reaches 12 cm/year in
the south and 16 cm/year in the north, with a minimum of 4 cm/year observed
near the central part of the margin
(Pelletier et al.
1998; Calmant et al.
2003). These high convergence rates produce a high level of
seismicity that each year yields more than 10 earthquakes of moment magnitude
(Mw) higher or equal to 6.0. Despite the area's high seismic potential and
volcanic hazards (Louat and Baldassari
1989; Eissen et . . . [Full Text of this Article]
Géosciences Azur
UMR 6526, IRD, CNRS, UNSA
250, rue
Albert Einstein
Sophia-Antipolis
06560 Valbonne,
France
pillet@geoazur.unice.fr
(R.P.)
Copyright © 2009 by Seismological Society of America