Huge Earthquake May Create Tsunami And Devastate Hawaii In 50 Years

By R. Siva Kumar - 16 May '16 10:48AM

Researchers from the University of Hawaii at Mānoa (UHM) find that the probability of a magnitude 9+ earthquake shaking the Aleutian Islands is about nine percent in the next half-century. It may lead to a tsunami that may overwhelm the residents, leading to a damage of almost $40 billion.

"Necessity is the mother of invention," said Rhett Butler, a geophysicist at the UHM School of Ocean and Earth Science and Technology (SOEST) and lead author of the study. "Having no recorded history of mega-tsunamis in Hawaii, 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."

With the Aleutian Islands being sensitive to a tsunami caused by an earthquake, Butler and his team made a numerical model that was based solely upon fundamental plate tectonics of fault length and plate convergence rate. They used Bayesian techniques to account for the uncertainties.

Since 1900, there had been five earthquakes greater than magnitude 9 at Tohoku, Sumatra-Andaman, Alaska, Chile and Kamchatka. The team validated their model based on the recorded histories and seismic/tsunami dates of the earthquakes.

"These five events represent half of the seismic energy that has been released globally since 1900," Butler said. "The events differed in details, but all of them generated great tsunamis that caused enormous destruction."

They also studied evidence shown by geological layers in coastal sediments, volcanic tephras, and archaeological sites.

"We were surprised and pleased to see how well the model actually fit the paleo-tsunami data," Butler said.

Hence, an earthquake of magnitude 9 in these greater Aleutians over the next half century is nine percent, with the margin of error being only three percent. The estimate of a risk from such data is estimated at $3.6 billion, equating $72 million per year.

The findings were published on April 20, 2016, issue of the Journal of Geophysical Research.