Ballu Valérie, Bonnefond P., Calmant Stéphane, Bouin M. N., Pelletier Bernard, Laurain O., Crawford W. C., Baillard C., de Viron O. (2013). Using altimetry and seafloor pressure data to estimate vertical deformation offshore : Vanuatu case study. Advances in Space Research, 51 (8), p. 1335-1351. ISSN 0273-1177.
Titre du document
Using altimetry and seafloor pressure data to estimate vertical deformation offshore : Vanuatu case study
Année de publication
2013
Auteurs
Ballu Valérie, Bonnefond P., Calmant Stéphane, Bouin M. N., Pelletier Bernard, Laurain O., Crawford W. C., Baillard C., de Viron O.
Source
Advances in Space Research, 2013,
51 (8), p. 1335-1351 ISSN 0273-1177
Measuring ground deformation underwater is essential for understanding Earth processes at many scales. One important example is subduction zones, which can generate devastating earthquakes and tsunamis, and where the most important deformation signal related to plate locking is usually offshore. We present an improved method for making offshore vertical deformation measurements, that involve combining tide gauge and altimetry data. We present data from two offshore sites located on either side of the plate interface at the New Hebrides subduction zone, where the Australian plate subducts beneath the North Fiji basin. These two sites have been equipped with pressure gauges since 1999, to extend an on-land GPS network across the plate interface. The pressure series measured at both sites show that Wusi Bank, located on the over-riding plate, subsides by 11 +/- 4 mm/yr with respect to Sabine Bank, which is located on the down-going plate. By combining water depths derived from the on-bottom pressure data with sea surface heights derived from altimetry data, we determine variations of seafioor heights in a global reference frame. Using altimetry data from TOPEX/Poseidon, Jason-1, Jason-2 and Envisat missions, we find that the vertical motion at Sabine Bank is close to zero and that Wusi Bank subsides by at least 3 mm/yr and probably at most 11 mm/yr. This paper represents the first combination of altimetry and pressure data to derive absolute vertical motions offshore. The deformation results are obtained in a global reference frame, allowing them to be integrated with on-land GNSS data.
Plan de classement
Géologie et formations superficielles [064]
;
Télédétection [126]
Description Géographique
VANUATU
Localisation
Fonds IRD [F B010060859] ;
Nouméa
Identifiant IRD
fdi:010060859
