Greater risk of quake, flood feared

The discovery of a previously unknown active fault in the Himalayas in Nepal means that the entire region is at great risk of life-threatening earthquakes and catastrophic flooding than previously thought, according to newly-published research co-authored by Mike Taylor, a University of Kansas geologist and five other scientists, reports BSS.
"Intense land slides could occur or intense ground shaking could breach glacially dammed lakes at higher elevations. This would cause catastrophic flooding of the more highly populated areas downstream," Taylor explained.
The discovery has changed geologists' understanding of the evolution of the tallest mountains in the world.
Published recently in the journal, Nature Geoscience, the research identified and mapped an earthquake rupture more than 63 kilometers (40 miles) long in the high elevations of the western Himalayas.
The Tibrikot fault is part of a much larger fault system that the researchers identified and named the Western Nepal Fault system, which is more than 350 kilometers (217 miles) long.
This system connects active faults in the Himalaya with faults in southern Tibet - a connection the scientists had not expected.
The researchers used radiocarbon dating to show that at least two earthquakes occurred along the fault and shifted the surface of the region by 5 metres each (16.4 feet) between 1165 and 1400 A.D. The quakes were probably of magnitude 7.9 or greater.
That is the same magnitude as the earthquake that devastated Sichuan, China, in 2008, killing nearly 70,000 people and leaving more than 18,000 missing.
"We previously thought the mountains were formed because the front of the range was shortened as it collided with India, much like what happens when you compress an accordion," Taylor said.
"Our findings indicate that the mountain belt is not only shortening, but is also simultaneously being stretched lengthwise at higher elevations along the newly identified fault systems."
The paper, "Limit of Strain Partitioning in the Himalaya Marked by Large Earthquakes in Western Nepal," was co-authored with MA Murphy and CRP Silver of the University of Houston, J Gosse and C Beaumont of Dalhousie University in Canada, and DM Whipp of the University of Helsinki in Finland.