Originally published September 11, 2015
By Nadia M. Whitehead
UTEP News Service
Five months after a devastating 7.8 magnitude earthquake hit Nepal, the ground still shakes.
But these days, University of Texas at El Paso (UTEP) geologists are ready — monitoring the Himalaya’s tremors closely. “There are magnitude four or five aftershocks every couple of days,” said Marianne Karplus, Ph.D., assistant professor of geological sciences, who recently returned from doing field work in the region.
Along with Aaron Velasco, Ph.D., a professor of geological sciences at UTEP, Karplus received a rapid response grant from the National Science Foundation to study the aftershocks of the April 25 earthquake in Nepal. The awards are given after disaster strikes when rapid access to data, facilities or equipment is needed. In this case, UTEP researchers — and collaborators at Stanford University, Oregon State University, the University of California, Riverside and the Department of Mines and Geology in Nepal — wanted to record aftershocks. These recordings could lead to better understanding and preparation for future earthquakes in the region.
And improved preparedness is crucial, Karplus said.
Despite its location in one of the most seismically active regions of the world, where the Indian tectonic plate is colliding with the Eurasian plate at a rate of about four to five centimeters per year, the quake revealed how vulnerable the country’s infrastructure is. More than 8,800 died and nearly 23,000 people were injured because of the natural disaster.
“It was very striking to see the villages,” Karplus said, recounting her trip to Nepal. “In some villages, every house was damaged. Roofs were down. Homes were flattened. In many cases, colorful tarps were being used as temporary roofs.”
Some major city buildings, she added, collapsed or sustained structural damage.
Scientists estimate that an even bigger earthquake — up to magnitude 8.8 — is on its way. That one would cause more devastation, killing as many as a million people. Stronger infrastructure could help, but first, researchers need to understand exactly how this last one occurred.
UTEP’s seismological research in the region will help scientists get answers.
45 seismometers, devices that measure ground movements, are currently scattered throughout the region. Karplus and geophysics doctoral students Mohan Pant and Ezer Patlan spent three weeks in Nepal deploying the systems, which will capture ground motion data for at least six months.
After receiving the NSF grant, the team flew to the country’s capital Kathmandu and, together with their Nepalese and U.S. collaborators, travelled to remote corners of the country to deploy the seismometers. They requested local farmers’ permission to place the equipment on their land.
“[The local people] would ask us questions like, ‘What were we doing there and what the machines were for,’” said Patlan. “When we explained to them, they were very receptive and happy because we were there to learn about and understand earthquakes.”
When approval was granted from a landowner, the team would dig two-foot deep holes to install the seismometers. They also set up solar panels and 12-volt batteries to power the instruments.
“The whole town would sometimes come to watch the process, which took three or four hours of hard labor,” Patlan said. “Villagers would offer to cook us meals while we were working and when we were done, some sent us off with bags of mangos or potatoes.”
The local farmers agreed to take care of the scientific equipment when the team wasn’t there.
“One woman even offered to have one her sons sleep next to the station at night for extra safety,” Patlan said. “We told them that wasn’t necessary, but it was so friendly of her to offer.”
Now back at UTEP, the geologists will receive the first few months of data from the seismometers this month. They plan to run some analyses to better understand the geometry of the Main Himalayan thrust, the fault line where the rupture occurred.
Karplus expects that the information they gather should hint at future seismic hazards in the region.
“Where the aftershocks are occurring and their motion can help us have a better understanding of how the fault works and exactly what happened,” Karplus explained. “It could also give us an estimation of whether there’s a high risk in the next 30 years of a similar event occurring.”
Depending on what’s discovered, infrastructure in Nepal could be fortified in preparation for larger, future quakes.