Three Earthquakes in Five Days: Are These Small Tremors in Delhi-NCR an Indication of a Big One?


Three Earthquakes in Five Days: Are These Small Tremors in Delhi-NCR an Indication of a Big One?

Illustration: Shruti Yatam

Tremors were felt in the national capital and areas surrounding it for a third time in just five days on Wednesday.

Although measuring just 3.2 on the Richter scale, which isn’t strong enough to cause any serious damage, the frequency with which earthquakes are being recorded in the National Capital Region has set some alarm bells ringing. Especially when considering the country is already facing a pandemic, a swarm of locusts, and recently saw off a cyclone on either coast.

Last week, an earthquake that recorded 4.5 on the Richter scale jolted parts of Delhi and Haryana. Tremors were felt a few days later, and a few days prior to that event. Reports say that as many as seven low-intensity earthquakes have been recorded in the last month.

While these tremors have been mostly harmless, could they also be a sign that something larger is on its way? According to recent studies in Los Angeles — which lies in another region that sees frequent earthquakes — there could be some evidence to suggest it does.

The report says that scientists had recently confirmed that most medium-intensity earthquakes follow a number of small “precursor events”. These foreshocks, it says, can start from three to 35 days ahead of the mainshock.

“This has added weight to the idea that earthquake sequences can grow, not unlike a spreading disease epidemic,” the report explains.

But that doesn’t mean every small shock will, in fact, lead to something bigger. In an article in Slate, a geophysicist also based in California, points out that the chance of a bigger earthquake following up on a smaller one is small (around 5%). This figure drops even lower over time.

Back in 2015, after one of the most devastating earthquakes the world has seen, struck Nepal and parts of India, China and Bangladesh, killing nearly 10,000 people, a number of scientists had indicated that it was a sign that something even larger was on its way.

One scientist quoted in Live Science, in fact, said that the disaster, which started over 4,000 landslides and brought Mount Everest closer to sea-level, was surprisingly gentle, when compared to past earthquakes in the region. This raised suspicions that the 2015 earthquake may have just been — and may still be — a precursor event.

So basically the short answer seems to be that pretty much all tremors and earthquakes lead to fears that a much larger one is on the way, but a very small percentage of these predictions turn out to be true. At this point, let’s hope 2020 doesn’t have the energy left anymore.