Sometime in the next 10 years we can expect an earthquake of a similar magnitude to the 2004 Sumatra quake that triggered the devastating Indian Ocean tsunami. So say Vladimir Kossobokov of the International Institute of Earthquake Prediction Theory and Mathematical Geophysics in Moscow, Russia, and colleagues, who have developed an algorithm to predict where and when such megaquakes will occur.
The team claims a global pattern emerges in the years before earthquakes of magnitude 9.0 or more. For example, the number of quakes caused by crustal movements between 300 and 700 kilometres below the surface rises, as does the incidence of those with a magnitude of 8.0 or more. Kossobokov points out that the four largest earthquakes of the 20th century happened within just 12 years, starting with the Kamchatka Peninsula quake in Russia in 1952, and culminating in the magnitude 9.2 quake in Prince William Sound, Alaska, in 1964. 鈥淭he chances of this happening randomly are less than 1 per cent,鈥� he says.
Alarm bells should be ringing over the fact that several quakes of magnitude 8.0 or stronger have happened in the past few years, the team says. What鈥檚 more, all the deep seismic faults around the globe are showing signs of increased activity. The algorithm shows that these events are redistributing stress along faults, putting five regions at risk: the Cascadia region in the west of the US and Canada; Chile and its neighbours; central America; the Himalayas, in particular Kashmir; and Sumatra and the Andaman Islands in the Indian Ocean.
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Kossobokov hopes the next megaquake will be the last of this bunch. 鈥淏ut history suggests that they are coming in numbers,鈥� he says.
The team presented its findings at the European Geosciences Union annual meeting in Vienna, Austria, last week.
