When the deadly earthquake struck Nepal on April 25th, it proved to be so violent that it literally moved mountains. New satellite topography of the Himalayas mountain range has revealed that they sank by three feet as tectonic plates reacted to pressure.
The European Space Agency’s Sentinel-1A radar satellite snapped before-and-after images of the terrain hit by the earthquake, which killed more than 8,000 people. The image, shown below, reveals how the Eurasian plate shifted, with the land falling in the places marked yellow, and rising in those coloured blue. In the Langtang range, it sank by as much as three feet, while Mount Everest, which was further away from the epicentre, is now one inch shorter.
The Himalayas will eventually regain the height that they lost over a long period of time, as geological forces continue to influence them. The mountain range was formed as a result of the Indian and Eurasian plates pushing into each other, and the constant pressure at the fault line means the mountains are always growing.
In the recent earthquakes, the plate under Kathmandu snapped like a rubber band, causing the reduction. Tim Wright, professor of satellite geodesy at the University of Leeds, explained what happened to the BBC:
“Between earthquake events, Nepal is being squashed and the part (including Kathmandu) nearest the big fault underneath it is being dragged down by the Indian plate, and [areas] further back are being lifted up as you imagine squashing something is going to push things up,” says Prof Wright.
“Now, during the earthquake itself what happens is the opposite. The part that was dragged down because it was stuck at the fault - that slips freely and rebounds up, and the part that was being squashed upwards drops down.”
