First mapping of a tsunami wavefield by SWOT satellite: observation data and preliminary numerical simulation of the 19 May 2023 tsunami near the Loyalty Islands

Roger, Jean H. M.; Faugère, Yannice; Hébert, Hélène; Delepoulle, Antoine; Dibarboure, Gérald

doi:10.5194/nhess-26-943-2026

Articles | Volume 26, issue 2

https://doi.org/10.5194/nhess-26-943-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/nhess-26-943-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 26, issue 2

Research article

|

27 Feb 2026

Research article |

| 27 Feb 2026

First mapping of a tsunami wavefield by SWOT satellite: observation data and preliminary numerical simulation of the 19 May 2023 tsunami near the Loyalty Islands

Jean H. M. Roger, Yannice Faugère, Hélène Hébert, Antoine Delepoulle, and Gérald Dibarboure

Data sets

Tsunami records with the NASA/CNES SWOT space altimeter Antoine Delepoulle et al. https://doi.org/10.57932/8b9996d3-c100-4a0a-ac67-05dd2e81155a

Short summary

Deployed in 2022, the SWOT (Surface Water Ocean Topography) satellite was flying over the Southwest Pacific on 19 May 2023 when it recorded the tsunami triggered by a magnitude 7.7 earthquake south of the Vanuatu arc. For the very first time, it provided a 2D image of a tsunami wavefield along a straight path. Comparison with numerical tsunami simulations reveals good phase agreement between the modeled wavefield and the SWOT record, but the simulated amplitudes are lower than the measurements.