New research partly funded by the Indian government to forecast earthquakes has made a grim prediction: a great quake never seen in centuries could strike Uttarakhand, an area home to 10 million people.
A 700-year-old ‘fault’ beneath the state has reached a tipping point, an Indo-Australian team of experts has concluded after gruelling lab and on-site investigations, including the scouring of three river-beds – those of the Bhagirathi, Alaknanda and Kali.
Notice of an impending earthquake may be scary, but it isn’t such a bad idea. Even seconds of advanced quake warning can reduce loss of lives, according to the US Geological Survey.
Quakes can’t really be predicted. But by using complex modern science, geologists can marry data sets from past quakes with slow changes in landscape patterns to tell where a tremor is due.
In two related studies, published in US journals Lithosphere and JGR, scientists arrived at a seemingly simple but common conclusion. Perched precariously on the edges of two colliding continental plates, Uttarakhand is “primed” for a “large” tremor.
“Decollement beneath Uttarakhand provides a sufficiently large and coherent fault segment capable of hosting a large earthquake. It is the most prominent gap not to have ruptured in about 500-700 years,” said one of the authors, CP Rajendran of the Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore.
In geology, décollement is a process in which some strata become detached. “Fault” is a gently curved fracture, while “strike” is the direction of a line formed by fault or other features.
It’s not just the discovery of all these features that made the team predict a large Uttarakhand quake. It’s the long time the fault has been taking to rupture — about 700 years — that makes a devastating quake in Uttarakhand overdue, Rajendran said.