ORCID Profile
0000-0002-3078-9052
Current Organisation
GNS Science Ltd
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Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 08-2021
Publisher: Copernicus GmbH
Date: 02-02-2023
DOI: 10.5194/NHESS-23-393-2023
Abstract: Abstract. The Vanuatu subduction zone (VSZ) is known to be seismically very active, due to the high convergence rate between the Australian and Pacific tectonic plates for the majority of the margin. However, this is not the case on its southernmost part south of latitude 22.5∘ S and east of longitude 170∘ E, which is neither highly tectonically active nor has it produced large tsunamis over the past 150 years. It has also not been widely studied. On the 11 February 2021 (10 February UTC), a magnitude Mw 7.7 earthquake triggered a tsunami warning in New Caledonia and Vanuatu 20 min after midnight (local time). With an epicentre located close to the volcanic islands of Matthew and Hunter, this shallow reverse-faulting rupture ( 30 km depth) was able to deform the seabed and produce a tsunami. This was confirmed 45 min later by the coastal gauges of the Loyalty and the south Vanuatu islands, which recorded the first tsunami waves. Showing a typical recorded litude of less than 1 m, with a maximum of ∼ 1.5 m in Lenakel (Tanna, Vanuatu), it was observed on most coastal gauges and DART stations in the south-west Pacific region as far as Tasmania to the south and Tuvalu to the north at distances of ∼ 3000 and ∼ 1800 km from the epicentre. In this study, the tsunamigenic potential of the southernmost part of the VSZ and the implications in terms of regional hazard assessment are discussed through (1) the presentation of the complex tectonic settings of this “transition zone” between the Solomon–Vanuatu and the Tonga–Kermadec trenches, (2) the case study of the 10 February 2021 tsunami at a south-west Pacific regional scale using three different tsunami generation scenarios computed with the COMCOT modelling code on a set of 48 nested bathymetric grids, and (3) the simulation of a plausible Mw 8.2 scenario encompassing the active part of this “transition zone”. The validation of the Mw 7.7 parameters for tsunami modelling provides the means to further assess the hazard from potential tsunamis triggered by higher magnitude earthquakes in this region. Tsunami records highlight that 28 cm wave litudes were recorded at eight different coastal gauges, including one with an litude of more than 1 m (Lenakel, Tanna, Vanuatu). The tsunami threat at that location would be large enough to warrant an onshore evacuation. Finally, it helps to highlight the significant role played by the numerous submarine features in the region, the Norfolk Ridge being the most important, which acts like a waveguide from the north to the south.
Publisher: Copernicus GmbH
Date: 07-06-2022
Abstract: Abstract. The Vanuatu subduction zone (VSZ) is known to be seismically very active, releasing a significant energy resulting of the quick convergence rate between the Australian and Pacific tectonic plates. That is not the case on its southernmost part south of latitude 22.5° S and east of longitude 170° E which is neither known as being highly tectonically active nor having produced large tsunamis over the past 150 years, and by the way, has not been much studied. On the 11th of February 2021 (10 February UTC), a magnitude Mw 7.7 earthquake triggered a tsunami warning in New Caledonia and Vanuatu twenty minutes after midnight (local time). With an epicentre located close to the volcanic islands of Matthew and Hunter, this shallow reverse-faulting rupture ( 30 km depth) was able to disturb the seabed and produce a tsunami. In fact, it was confirmed 45 min later by the coastal gauges of the Loyalty and the south Vanuatu islands which recorded the first tsunami waves. Showing an overall recorded litude of less than 1 m with a maximum of ~1.5 m in Lenakel, (Tanna, Vanuatu), it has been recorded on most coastal gauges and DART stations of the southwest Pacific Region as far as Tasmania in the South and Tuvalu in the North respectively at distances of ~3000 and ~1800 km from the epicentre. In this study, the tsunamigenic potential of the southernmost part of the VSZ and the implications in terms of regional hazard assessment are discussed through (1) the presentation of the complex tectonic settings of this “transition zone” between the Solomon-Vanuatu and the Tonga-Kermadec Trenches (2) the case study of the 10 February 2021 tsunami at a southwest Pacific regional scale using three different tsunami generation scenarios computed with COMCOT modelling code on a set of 48 nested bathymetric grids and (3) the simulation of a plausible Mw 8.2 scenario encompassing the active part of this “transition zone”. In fact, the validation of the Mw 7.7 parameters for tsunami modelling provides keys to further assess the hazard from potential tsunami triggered by higher magnitude earthquakes in this region. Finally, it helps to highlight the significant role played by the numerous submarine features in the region, the Norfolk Ridge being the most important acting like a waveguide toward the north and the south.
Publisher: Copernicus GmbH
Date: 22-07-2019
DOI: 10.5194/NHESS-19-1471-2019
Abstract: Abstract. Fourteen years ago, the 26 December 2004 Indian Ocean tsunami demonstrated the destructional capability of tsunamis to the entire world. Since then, many research programs have been initiated to try to understand the phenomenon and its related hazards better and to improve the early warning systems for exposed coastal populations. Pacific Islands Countries and Territories (PICTs) are especially vulnerable to tsunamis. Amongst them, New Caledonia is a French overseas territory located in the Southwest Pacific and exposed to several tsunami sources. In 2010, a catalogue of tsunamis that were visually observed or measured in New Caledonia was published. Since this first study, several events occurred between 2009 and 2019, and an update of this catalogue was necessary within the framework of a tsunami hazard assessment project in New Caledonia (TSUCAL). To complete this catalogue, a decision table has been designed to select potential tsunamigenic events within the USGS earthquake database, using criteria on the distance to New Caledonia, the magnitude and the hypocenter depth. Then a cross-comparison between these earthquakes, the NOAA National Geophysical Data Center (NGDC) tsunami catalogue and local tide gauge records provided 25 events that were recorded in New Caledonia for the period from 30 September 2009 to 10 January 2019. These events are added to the 12 events reported with certainty during previous studies, leading to a number of 37 tsunamis triggered by earthquakes reported or recorded in New Caledonia since 1875. Six of them have been identified only thanks to local tide gauges, supporting the fact that instrumental recording of tsunamis is paramount for tsunami hazard studies, from early warning to the validation of coastal models. In addition, unpublished tide gauge data are provided for the 1960 Chile tsunami.
Publisher: Copernicus GmbH
Date: 26-02-2019
Abstract: Abstract. 14 years ago, the December 26, 2004 Indian Ocean tsunami brought to the entire World the destruction capability of tsunamis. Since then, many research programs have been initiated to try to better understand the phenomenon and its related hazards, and to improve the early warning systems for the exposed coastal populations. Pacific Islands Countries and Territories (PICTs) are especially vulnerable to tsunamis. Amongst them, New Caledonia is a French overseas territory located in the South-western Pacific and exposed to several tsunamis sources. In 2010, a catalogue of tsunamis that were visually observed or measured in New Caledonia was published. Since this first study, several events occurred between 2009 and 2019 and an update of this catalogue was necessary within the framework of a tsunami hazard assessment project (TSUCAL). To complete this catalogue, a decision algorithm has been designed to select potential tsunamigenic events within the USGS earthquake database, using criteria on the distance to New Caledonia, the magnitude and the hypocenter depth. Then a cross-comparison between these earthquake events, the NOAA NGDC tsunami catalogue and local tide gauge records provided 25 events that were recorded in New Caledonia for the period from September 30, 2009 to January 10, 2019. These events are added to the 12 events reported with certainty during previous studies, leading to a number of 37 tsunamis triggered by earthquakes reported in New Caledonia since 1875. Six of them have been identified only thanks to local tide gauges, supporting the fact that instrumental recording of tsunamis is paramount for tsunami hazard studies, from early warning to the validation of coastal models. In addition, previously unpublished data is provided for other already reported tsunamis as well as tsunamis with unspecified date and source.
Publisher: Springer Science and Business Media LLC
Date: 13-11-2010
Location: France
Location: France
Location: France
Location: Guadeloupe
No related grants have been discovered for Jean Roger.