The massive earthquake that struck Nepal this April could have caused a lot more damage, but the Himalayan nation isn't out of the woods yet.
Nepal suffered a devastating earthquake this April, leaving thousands dead and even more displaced. According to a report from the BBC, however, the earthquakes that rocked the small Himalayan nation could have been even worse, and officials are rushing to address the infrastructural issues that led to much of the devastation before it can happen again.
The Gorkha earthquake measured 7.8 on the Richter scale, and left vast swaths of South Asia completely devastated. The study, conducted by researchers from the University of Arizona, Tuscon, used satellite imaging to figure out exactly what went wrong, leading to widespread property damage and destruction.
The assessment showed that the number of landslides in the area surrounding the earthquake was far lower than it might have been if the conditions were different. The study also found no evidence that the glacial lakes of the Himalayas had been damaged, which is good news for people living in the region.
The study’s findings were published in Science magazine, and will be presented at the Fall Meeting of the American Geophysical Union in San Francisco where Earth scientists from around the globe will gather to share research. According to the study’s lead author, Jeffery Kargel from the University of Arizona, Tuscon, the findings were unexpectedly surprising.
“The nature of the earthquakes’ influence on the landscape, from the largest scales to the smaller scales,” Kargel said, “was not really as we would have expected.”
The main tremor that hit Magnitude 7.8 on the 25th of April this year happened as the Himalayan plate lifted up the Kathmandu basin as they converged. The entire region was shifted 2 meters to the south as a result of the earthquake.
Geologists originally expected the earthquake to precipitate thousands of landslides, but a volunteer satellite study showed that only about 4,312 landslides occurred as a result of the quake. Scientists also feared that the glacial lakes held in place by loose deposits of rocks would have been breached and spilled out into the valleys of the Himalayas. The satellite images revealed that there was no serious damage to any glacial lake as a result of the earthquake either.
There are a number of theories as to why the earthquake didn’t cause more damage than it did. Some believe that the nature of the shaking, which was smooth and uniform despite its high amount of energy, could have had a significant effect in keeping damage to the environment relatively low. Other theories suggest that the rock was more coherent than researchers originally thought, or that the vegetation on the mountainsides played a key role in keeping things together.
Despite the devastation caused by the Gorkha earthquake this spring, the damage could have been a lot worse. The village of Langtang, a small trekking stop north of Kathmandu, had it particularly bad. According to Brian Collins from the U.S. Geological Survey, “It started off as a snow and ice avalanche somewhere above 5,000m and then slid over 1,000m before going off a cliff and into free-fall for about 500m; and that free-fall was really the damaging aspect of it.”
Earthquakes convert the stored potential energy of rocks and soil sitting high above the earth into kinetic energy, which leads to massive structural damage on nearly anything manmade. Luckily, the earthquake did not result in all-out devastation for the country. Hopefully, officials will heed the study’s warnings and wok to address any weaknesses in Nepal’s infrastructure before it can happen again.
A press release from the University of Arizona describing the details of the study can be found here.