On December 26, 2004, (click here) the Great Sumatra-Andaman earthquake struck with an estimated magnitude of at least 9.1 and spawned tsunamis across the Indian Ocean that killed more than 225,000 people. Just three days earlier another great earthquake, with a magnitude of 8.1, struck Macquarie Ridge.
“But there was no tsunami because the plates were moving laterally past each other,” said Mosher. Tsunamis occur when seafloor rapidly moves up or down, setting large volumes of water in motion. “As the plate boundary evolves to more and more subduction with time we will get earthquakes with large vertical motion at Macquarie Ridge and with the potential for tsunamis.”
Felt throughout Tasmania, Australia and felt in Southland, West Coast and other parts of the South Island, New Zealand.
