Home Emergency Management News Study: 9 Percent Chance of Megaquake in Aleutian Islands in Next Five Decades

Study: 9 Percent Chance of Megaquake in Aleutian Islands in Next Five Decades

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Scientists estimate likelihood of mega-earthquake in the Aleutians

Researchers from the University of Hawaii at Manoa (UH Manoa) recently published a study that examined the likelihood of a mega-earthquake event in the Aleutian Islands and estimated the probability of such an event occurring on the next 50 years.

According to the findings of the study, the probability of a magnitude-9.0 or greater earthquake occurring in the Aleutians within the next five decades in approximately 9 percent. The impact of an Aleutians quake of such extreme magnitude is of special significance to Hawaii, as a megaquake would likely create a tsunami that would threaten the island state.

Aleutian Islands

The Aleutian Islands are a chain of 69 islands -- 14 large volcanic islands and 55 smaller islands -- that extend for approximately 1,100 miles separating the Bering Sea in the north from the Pacific Ocean in the south. The majority of the islands in the archipelago belong to the United States (Alaska), but a group on the western end belongs to Russia. The group of islands has a total area of about 6,821 square miles, is home to 57 volcanoes, and is considered to be part of the Pacific Ring of Fire.

Hawaii tsunami & projected costs

According to the UH Manoa researchers, Hawaii is especially vulnerable to a potential tsunami that could be created by an earthquake in the subduction zone of the Aleutian Islands. While the research team is planning to eventually extend its analysis to smaller earthquakes -- roughly magnitude-7.0 to magnitude-8.0 -- the analysis in this study was done specifically with mega-earthquakes in mind, quakes of magnitude-9.0 or larger. And a megaquake has the potential to create a mega-tsunami.

A 2013 State of Hawaii Multi-Hazard Mitigation Plan estimated Hawaii's tsunami risk at approximately $40 billion and listed the "total resident population of area at immediate risk to post-tsunami impacts" at 400,000. Structures at risk include 1,000 buildings directly relating to the tourism industry, 3 international airports, 3 regional power plants; 100 government buildings, and many other buildings -- including military structures.

With that $40 billion figure in mind, and also taking into consideration the UH Manoa study risk figure of 9 percent, this, according to the study, places an overall $3.6 billion figure on tsunami risk in Hawaii. And, annualized over 50 years, this risk calculates to approximately $72 million per year.

The researchers hope that by calculating the probability of a seismic event through research, and connecting that probability to cost estimates from official studies, the state will be able to "prioritize this hazard with other threats and needs."

Matt Mills Matt Mills has been involved in various aspects of online media, both on the editorial side and on the technology side, for more than 16 years. He holds a Master's Degree in Journalism from Northwestern University's Medill School of Journalism, and is currently involved in multiple projects focused on innovation journalism.