Strong quake rerouted Ganga 2,500 years ago: Study

Another similar tremor may recur, cause devastating floods in the delta region

- Shankar Raj

A new study has found that the mighty Ganga had changed its route following a massive earthquake and rerouted the river. The study says the delta's central river channel has not moved in centuries. But it shifted dramatically 2,500 years ago when a massive earthquake struck the region.

Its authors say a similar quake-induced shift in the Ganga now could mean a "devastating modern occurrence" of unprecedented flooding.

Discovery of new seismic concern stokes flooding fear for the densely populated delta region, the authors of the study published in the latest issue of Science journal said.

"Rivers occasionally flow over their banks to create a new path, a phenomenon known as an avulsion. Within river deltas, the main path of the water, the river channel, can move every millennium or so," said geoscientist Elizabeth Chamberlain of Wageningen University & Research, lead author of the study published on Monday in Nature Communications.

But avulsions generally "take place over decades" as a river gradually shifts its banks, said co-author Michael Steckler, a geophysicist at Columbia University's Lamont-Doherty Earth Observatory.