Explained: Why Western Nepal Is More Prone to Earthquakes

Three earthquakes struck western Nepal in a span of few days.

Over the past week, Nepal experienced three earthquakes in a span of a few days. A 5.2 magnitude earthquake struck Nepal on Monday, 6 November, followed by another slightly weaker one in which three people were injured.

On 3 November, an earthquake struck Jajarkot district in western Nepal, about 550 kilometres from Kathmandu, the tremors of which were also felt in Delhi and parts of north India. The natural disaster has left at least 155 dead.

All of these quakes occurred in western Nepal. Monday's tremors was the most powerful one since the 7.8 magnitude earthquake in 2015, where the epicentre was reportedly in eastern Nepal and claimed the lives of around 9,000 people.

There have been a total of 70 earthquakes of magnitude 4.0 and above in Nepal, according to the Earthquake Monitoring and Research Centre from 1 January 2023 till date.

Of these, about 13 were between 5.0 and 6.0 in magnitude while three others recorded magnitudes above 6.0.

But why is western Nepal an earthquake-prone zone in the first place? The Quint explains.

Nepal's Location in Seismic Zone

Nepal is located in the Himalayan region which is a highly seismic zone. The mountainous country is the 11th most earthquake-prone country in the world, according to the Nepal government's 'Post Disaster Needs Assessment' (PDNA) report published in 2015.

The Earth’s outermost layer, known as the crust, is made up of tectonic plates. And Nepal happens to sit on the fault lines of two major tectonic plates, the Eurasian and Indian tectonic plates.

"The entire country is seismic, the entire Nepal is seismic,” Amod Mani Dixit, the director of the National Society for Earthquake Technology in Kathmandu, told The Quint.

"This is evidenced by the fact that the country has experienced six large/damaging earthquakes with magnitudes equal to or greater than 7.6. As per historical records, Nepal experienced large earthquakes in 1255, 1408, 1505, 1833, 1934, and 2015," he added.

More Earthquakes in Western Nepal's Future?

Dixit also explained why the quakes occurred in the hilly areas in Nepal’s western region, which is particularly vulnerable. "The region had accumulated intense strain seismically since previous quakes, and had not matched the safety measures put in place in the eastern region since 2015," he added.

Bharat Koirala, a senior seismologist at the National Earthquake Monitoring and Research Centre in Nepal, told The Quint, "studies have pointed out that at least four, and possibly up to eight, major earthquakes over the last 800 years have taken place in central and eastern Nepal. However, the last known major seismic event to have affected western Nepal was in 1505."

"So, essentially, there had been a seismic gap in western Nepal up until the recent tremors. There was a massive build-up of energy as a result of which the inevitable happened: the energy got released through an earthquake. It was like a Damocles sword hanging over Nepal's head."

Bharat Koirala, seismologist

He added that there is always the risk or possibility of occurrence of a bigger earthquake in western Nepal in the future.

Dhruba Khadka, a spokesperson for Nepal's National Disaster Risk Reduction and Management Authority, told the local media that scientists had warned that an earthquake was likely to strike the western part of the country.

Surya Narayan Shrestha of the National Society for Earthquake Technology (NSET) told The Quint that despite still being the most at risk, western Nepal is less prepared and has relatively low awareness about earthquake safety.

Immediately after the 2015 disaster, the Nepal government had ordered provincial and local governments to prepare action plans and enforce building codes. However, according to a report by The New York Times, the implementation of these measures have been poor.

The report highlighted that building regulations have been implemented only in a few cities. It pointed out that enforcement of such codes was “pathetic” especially in the hilly areas of western Nepal.