<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/gettyimages-1171035329.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/gettyimages-1171035329.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/gettyimages-1171035329.jpg?v=ap&w=980&h=551 800w" > People walk on a damaged road a day after the strong earthquake in Jatlan town in the Mirpur District near India-Pakistan border, on Sept. 25, 2019. Death toll from Tuesday's strong earthquake has reached 37. (Chudary Naseer/Anadolu Agency via Getty Images)

On Tuesday evening, residents of multiple north Indian states were shocked when the earth began shaking vigorously. The quake lasted for a few seconds, but they took a huge toll. At least 37 people were killed due to the 6.3-magnitude earthquake on the banks of River Jhelum near the India-Pakistan border. Tremors were felt across north India including Jammu and Kashmir, Uttarakhand, Punjab, Haryana, Himachal Pradesh, and Delhi.

The Himalayas: an earthquake hotspot

In September alone, the Himalayan fault line along the Indian subcontinent has witnessed over 15 earthquakes so far. This 2,400-km-long stretch from Gujarat to Myanmar passes through Kashmir, Nepal and Arunachal Pradesh. The Himalayan region is one of the most seismically active areas on earth because of an ongoing collision between two continental plates: the Indian and the Eurasian.

“The Himalayan zone is a plate boundary. And the plate boundaries are usually the earthquake hotspots. If one plots the major earthquakes in the Indian subcontinent on a map, there all in this one single zone. Major cities like Delhi fall under this earthquake-prone zone,” explains Dr H N Udaya Shankara, Professor at Manipal Institute of Technology.

The Indian plate is continuously moving northward by a few centimetres each year. This constant march causes its subduction under the Eurasian plate. The movement is irregular, with periodic jerks that release the stress built up in the rocks.

<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/gettyimages-1170772131_0.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/gettyimages-1170772131_0.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/gettyimages-1170772131_0.jpg?v=ap&w=980&h=551 800w" > A news cameraman films a damaged road following the earthquake on the outskirts of Mirpur on Sept. 24, 2019. (Aamir Qureshi/AFP/Getty Images)

“It is all a simple stress and strain mechanism. Whenever the rocks get more stressed, they release the energy, and it results in an earthquake. So, we can only identify the regions susceptible to earthquakes but cannot predict when will it happen,” says Dr Shankara.

Stronger quake on cards

The long-term seismological analysis in the region shows that the amount of energy getting accumulated in the subduction zones is not equally dissipated through the small and moderate earthquakes that we see right now. The energy has been building up, and the only relief is a strong earthquake.

Consequently, an earthquake of magnitude higher than eight has been projected in the region. To compare, the Nepal earthquake of 2015 was of magnitude 7.8, and it claimed over 8,800 lives. With the available technologies, it is impossible to predict when exactly an earthquake will happen. Scientists, therefore, urge the people and authorities to be prepared.

“It is important to comply with building codes and construct earthquake-resistant structures, especially in these vulnerable regions,” says Dr Shankara. “Studies predict that a powerful earthquake is on the cards for this region. When? Only time can tell.”