Study predicts chance of 9+ magnitude mega-earthquake in the Aleutians

June 2016 – ALASKA – There’s a nine percent chance a magnitude 9 or larger earthquake will strike the Aleutian Islands in the next 50 years. That is the prediction offered by scientists from the University of Hawaii at Mānoa — made with the help of a newly designed computer model. Researchers say an earthquake of that size could send a mega-tsunami in the direction of the Hawaiian Islands.

The Aleutian Islands, which stretch toward Russia from the coast of Alaska, sit along a subduction zone at the convergence of the Pacific and North American tectonic plates. Scientists say the chance of a dramatic slip along the fault lines that make up the subduction zone is significant. They detailed the threat of a mega-earthquake in a new paper, published this week in the Journal of Geophysical Research – Solid Earth.

“Necessity is the mother of invention,” lead study author Rhett Butler, a geophysicist at the UHM School of Ocean and Earth Science and Technology, explained in a news release. “Having no recorded history of mega tsunamis in Hawai’i, and given the tsunami threat to Hawaii, we devised a model for Magnitude 9 earthquake rates following upon the insightful work of David Burbidge and others.” Researchers integrated fault system measurements — fault length and convergence rate — with Bayesian probability models, and then tested the predictions against historic tectonic events.

Researchers compared the simulation to recent catastrophic earthquake and tsunami events, including Sumatra-Andaman in 2004; Alaska in 1964; Chile in 1960; and Kamchatka in 1952. “These five events represent half of the seismic energy that has been released globally since 1900,” said Butler. “The events differed in details, but all of them generated great tsunamis that caused enormous destruction.” Researchers further refined the model by incorporating ancient evidence of tsunami events found in the archaeological and geologic records. “We were surprised and pleased to see how well the model actually fit the paleo-tsunami data” concluded Butler. The scientists are now working to augment the model in order to predict smaller earthquakes.   –UPI