[Source: 1news]

Australian and New Zealand experts say while not all major earthquakes will trigger tsunamis, the one in Vanuatu today is expected to have caused significant structural damage due to its depth.

Adam Pascale, the Chief Scientist at the Seismology Research Centre earthquake observatory in Melbourne, says the depth of the 7.3 magnitude event in Vanuatu rather than the type of rupture that would have caused the type of devastation witnessed there so far.

“Not all offshore large magnitude earthquakes generate a tsunami, due to reasons such as earthquake depth and the orientation of the rupture of the fault,” he said.

“It is prudent to issue tsunami warnings if predetermined criteria are met, and equally important to clear warnings once there is evidence that the threat of tsunami is no longer active.”

Aftermath of 7.4 Earthquake in Port Vila, Vanuatu
Extensive damage to the buildings.
December 17, 2024 #earthquake #sismo #terremoto pic.twitter.com/jGBkKwyYmp

— Disasters Daily (@DisastersAndI) December 17, 2024

Pascale says this occurred two weeks ago when a magnitude 7.0 earthquake occurred off the coast of California, and again today for the magnitude 7.3 earthquake that struck just off the coast of Port-Vila.

“I explored tsunami warnings in a short TikTok video a week ago. In today’s earthquake it was more likely the depth of the event rather than the type of rupture that prevented the tsunami being generated.”

Professor Meghan Miller, Director of the AuScope Earth Imaging Program in the Research School of Earth Sciences at the Australian National University, says the earthquake occurred at the boundary between the Australia and Pacific plates near Vanuatu.

“In this region, where the tectonic plates converge is one the world’s most seismically active plate boundaries,” she said.
“The earthquake hypocentre was fairly deep, about 57 km, which means there was no tsunami generated. However, the capital city Port Vila is located only ~30 km away from the epicentre, and the island experienced very strong shaking, likely resulting in moderate damage to structures.”

Associate Professor Kasper van Wijk from the Department of Physics at the University of Auckland, says there are similarities between Vanuatu and New Zealand when it comes to earthquake activity.

“Vanuatu is situated, like New Zealand, on top of a subduction zone,” he said.

“This particular earthquake was shallow and close to Port Vila, so I expect there to be significant damage from the earthquake. From recordings of the seismic waves, it appears this earthquake could also have the ingredients for a tsunami, specifically for the Islands in the region. The hypocentre was in the crust overlain by the Pacific Ocean, and there may have been the rapid uplift of the crust under the water needed for a tsunami.”