Vanuatu earthquake: Tsunami threat ends after alert is revised
Illustration: a conceptual Pacific earthquake and lifted-alert graphic, not a map or depiction of the actual event. Generated by OpenAI for CrispNG.
The tsunami threat from the strong earthquake off Vanuatu had passed by the time the Pacific Tsunami Warning Center issued its final regional message. The center revised the quake’s preliminary magnitude from 7.2 to 6.9 and said no tsunami threat remained. That cleared the tsunami alert; it did not mean seismic activity had stopped.
Vanuatu earthquake: What happened?
The U.S. Geological Survey places the magnitude 6.9 earthquake at 02:31 UTC on October 24, about 197 kilometres west-northwest of Port-Olry, at a depth of 10 kilometres. The Pacific Tsunami Warning Center’s first message used a preliminary magnitude of 7.2 and warned that hazardous waves were possible along coasts within 300 kilometres of the epicentre.
In message No. 2, issued at 03:28 UTC, the center revised the magnitude to 6.9 and said the tsunami threat had passed. It said minor sea-level fluctuations could still occur near the earthquake over the following hours and advised normal caution near the sea. Its message was for national authorities, which determine local alert levels.
Vanuatu earthquake: Is the tsunami threat over?
The center’s final message said there was no longer a tsunami threat from this earthquake. The U.S. tsunami system now lists no warning, advisory, watch or threat in effect for the event. This is distinct from saying that no wave or sea-level change was observed: the center warned that minor fluctuations remained possible near the epicentre. For a separate example of an undersea quake that prompted a tsunami alert, see CrispNG’s Japan earthquake safety update; the events and local warnings are different.
Why aftershocks still matter
The warning was about tsunami danger, not the risk of further shaking. The Associated Press reported a second preliminary magnitude 6.3 earthquake and said several aftershocks followed the main event. Vanuatu’s Meteorology and Geo-Hazards Department catalogue lists a series of later earthquakes in the region, including entries of magnitude 6.0 at 08:56 UTC and 4.9 at 10:37 UTC on October 24.
Those catalogue entries show that seismic activity continued after the tsunami threat was cleared. They do not establish that every event was felt or caused damage. Earthquake agencies may also report different preliminary magnitudes as they process observations, so the agency and time attached to a figure matter.
What is known about damage?
The AP’s initial report said there were no immediate reports of damage. That is an early snapshot, not a final damage assessment for all communities. The sources reviewed do not provide a later comprehensive count of injuries, damage or displaced residents.
For coastal residents, the practical distinction is to follow current instructions from Vanuatu’s local authorities. The Pacific center’s event-specific tsunami threat has passed, while the official earthquake catalogue remains the place to check for later seismic reports.
Sources: Pacific Tsunami Warning Center final message; U.S. Geological Survey event record; Vanuatu Meteorology and Geo-Hazards Department earthquake catalogue; Associated Press report; AFP report.