The 2024 M7.3 Vanuatu earthquake: an overview

The 17^th of December 2024, a deadly M7.3 earthquake struck Port Vila, the capital of Vanuatu. This earthquake, located 30 km West of Port Vila, was strongly felt and damaged heavily the city economical center. This earthquake shows an unusual focal mechanism: a nearly-vertical fault with slip predominantly along-dip, and with strike perpendicular to the Vanuatu subduction. Comparing this earthquake with regional focal mechanisms for 30 years shows the uniqueness of this event. A local seismic network recorded a precursory seismic sequence (we detail this in another presentation, EGU25-16072). In this study we analyze the position time series recorded by a continuous GNSS station located in Port Vila, putting it in relation with the local and regional seismotectonic context, with a focus on the weeks preceding the mainshock and on the coseismic displacement. Finally, using Coulomb stress modeling and analyzing the spatio-temporal evolution of the seismicity in the neighboring subduction, we examine the potential impact of this earthquake on the subduction behavior.