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Study: Kink in Nepal fault line works as Himalayan growth plate

The same forces that prop up the mountains ultimately caused the deadly earthquake that devestated Nepal in April 2015.

By
Brooks Hays
New satellite data allowed scientists to analyze the changes in elevation and ground movement before, during and after the Nepalese earthquake that rattled the Himalayas in 2015. File photo by NASA/UPI
New satellite data allowed scientists to analyze the changes in elevation and ground movement before, during and after the Nepalese earthquake that rattled the Himalayas in 2015. File photo by NASA/UPI | License Photo

CAMBRIDGE, England, Jan. 11 (UPI) -- Improved satellite technology has allowed a team of researchers to map the fault line dividing Nepal in greater detail than ever before.

The new map -- and the geologic algorithms that made it possible -- has revealed a kink responsible for the growth of Himalayan peaks and the 2015 quake. The findings also suggest a future rupture is likely to happen relatively soon.

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The newly discovered kink in the Nepalese fault line has created a ramp some 12 miles beneath the surface. Over time, more material is pushed up the ramp, edging the peaks above higher and higher. As this happens, pressure builds up in the fault line.

"The earthquake itself then reversed this, dropping the mountains back down again when the pressure was released as the crust suddenly snapped in April 2015," lead researcher John Elliott, a scientist at Oxford University, explained in a press release.

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In other words, the same forces that prop up the mountains ultimately caused the deadly earthquake that devestated Nepal in April 2015, claiming the lives of more than 8,000 people.

Elliott is the author of a new paper on the latest revelations, published this week in the journal Nature Geoscience.

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Lidar satellite measurements show that the mountains above the earthquake zone dropped more than 23 inches in the seconds following the violent fault slip.

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"We successfully mapped the earthquake motion using satellite technology on a very difficult mountainous terrain," said Pablo Gonzalez, a member of the research team and scientist at the University of Leeds. "We developed newly processing algorithms to obtain clearer displacement maps, which revealed the most likely fault geometry at depth. Such geometry makes sense of the puzzling geological observations."

The new analysis also shows that the fault's rupture ceased nearly 8 miles below Kathmandu. Several miles of fault line remain undamaged. The rupture's propagation up the fault line was thwarted by interactions with old faults.

This premature pause may mean another earthquake will come relatively soon.

"Work on other earthquakes has suggested that when a rupture stops like this, it can be years or decades before it resumes, rather than the centuries that might usually be expected," Elliott said. "Unfortunately, there is no way of predicting precisely when another earthquake will take place. It's simply a case of countries and cities making sure they are well prepared for when it does happen."

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