Tuesday’s 7.8 magnitude temblor near the Iran-Pakistan border could realign the region’s tectonic plates, potentially setting off follow-up earthquakes closer to India in the coming days and weeks, scientists have cautioned.
From Ahmedabad in Gujarat to Nongpoh in Meghalaya, India was on Tuesday shaken by a ring of earthquakes that scientists say were most likely unrelated, but could trigger aftershocks. The quakes have triggered fresh concerns over preparedness in the country’s burgeoning urban spreads.
The Iran quake occurred close to the line where the Indian and Eurasian tectonic plates meet, west of Gujarat in Pakistan. Proximity to that line makes western India — home to Latur, Maharashtra and Bhuj, Gujarat that were epicentres of two of India’s most destructive recent earthquakes — vulnerable.
“When a major earthquake occurs on one plate near where it meets another plate, it causes shifts on the other adjoining plate,” Ramancharia Pradeep Kumar, earthquake engineer and professor at the Indian Institute of Information Technology in Hyderabad told HT. “There will also be aftershocks in neighbouring areas.”
Though most aftershocks occur within 24 hours, there have been instances of the follow-up tremors waiting for weeks before striking.
A quake measuring 4.4 on the Richter Scale with an epicentre in Nongpoh, Meghalaya triggered tremors across northeast India and even Odisha early on Tuesday morning. It was 49.2 km deep. Deeper quakes cause less damage as they lose most of their energy by the time they reach the earth’s surface.
Early afternoon, just after 2pm, a second quake shook northeast India. This 5.3 magnitude earthquake had its epicentre in Motuo in eastern Tibet, and was 31 km deep. A few hours later, the biggest quake of the day struck, near Khash in Iran.
The sequence of the quakes and the distance between eastern Tibet and Iran makes it highly improbable that the two were related, said BK Rastogi, Director of the Institute of Seismological Research in Gandhinagar.
But the quakes have cast fresh focus on India’s preparedness to handle large quakes closer home.
After the 2001 Bhuj earthquake that killed about 20,000 people, India set up a National Disaster Management Authority (NDMA) to formulate a strategy for national crises. Several states have also set up similar agencies.
But when it comes to ensuring earthquake-resistant building codes, little has been done, the scientists said. “The only solution is to make earthquake-resistant design non-negotiable for buildings,” Kumar said.