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Source and Impact Characterization of the M7.3 2024 Port Vila, Vanuatu, Earthquake

Description: 

On December 17, 2024, a magnitude 7.3 earthquake occurred 30 km offshore of Vanuatu’s capital, Port Vila. The rapid source characterization by the U.S. Geological Survey (USGS) estimated that the earthquake had an oblique normal faulting mechanism with a depth of 57 km, indicating that it was an intraslab rupture within the subducting Australian plate. Despite being relatively deep and located offshore, the earthquake caused extensive damage and destruction to the housing and infrastructure. The earthquake caused the collapse of nearly a dozen buildings in Port Vila, leading to at least 14 fatalities and over 265 injuries, including a notable partial collapse of the building that housed the U.S. Embassy. The shaking from the event also triggered numerous landslides, lateral spreads, and landslide dams.

We present rapid response products produced by the USGS and GNS Science and show their insights into the seismotectonic framework of the region. We also use rupture kinematics and aftershocks to identify the causative fault plane. We compare impact products to post-event observations, emphasizing how these events evolve as we gain further insight into source properties. While large earthquakes are common along the New Hebrides trench, many hazards associated with these events are linked to their potential for tsunamis, as they largely occur offshore. This event reminds us that ground shaking and coseismic landslides can be significant hazards on islands along active subduction zones. Such hazards can persist for many years post-earthquake due to an increase in the frequency of aftershocks and the increased susceptibility of the earthquake-damaged slopes to post-earthquake rainfall-induced landslides. For example, many of the coseismic landslide dams breached within the first few weeks post-formation, resulting in debris flows and floods and affecting people living downstream who had been evacuated in anticipation of such hazards. Robust monitoring and source characterization is critical to ensure a comprehensive understanding of seismic hazards and the cascading hazards they can cause in the region.

Session: Late-breaking on Recent and Future Large Earthquakes [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: William

Student Presenter: No

Invited Presentation: 

Poster Number: 148

Authors