At least 4 tremors in 30 days, why is Delhi NCR rocked by repeated earthquakes?
2 min read 22 Mar 2023, 06:53 PM ISTA strong earthquake with a magnitude of 6.5 struck Afghanistan, Pakistan, and parts of North India on Tuesday night, causing panic among residents who rushed out of their homes.
PremiumA strong earthquake with a magnitude of 6.5 struck Afghanistan, Pakistan, and parts of North India on Tuesday night, causing panic among residents who rushed out of their homes.
The US Geological Survey reported that the epicenter was located 40 kilometers south-southeast of Jurm, in Afghanistan's mountainous Hindukush region, bordering Pakistan and Tajikistan. The quake struck 188 kilometers deep below the Earth's surface, making it felt over a wide area. According to an Associated Press report, 11 people have died in Afghanistan and Pakistan as a result of the quake.
But why Afghanistan and Pakistan are prone to earthquakes?
Experts have said that Afghanistan is particularly vulnerable to earthquakes due to its location in the Alpide belt, which is the second most seismically active region in the world after the Pacific Ring of Fire. The Alpide belt runs about 15,000 kilometers from the southern part of Eurasia through the Himalayas and into the Atlantic, including the Hindu Kush, the Alps, Atlas Mountains, and the Caucasus Mountains. The boundary between the Indian and Eurasian plates exists near Afghanistan's border with Pakistan.
Moreover, poor infrastructure in Afghanistan exacerbates the impact of earthquakes. Many buildings in the country are not earthquake-resistant, and they are often made of timber, adobe, or weak concrete, Dr Brian Baptie, seismologist with the British Geological Survey, commented while speaking to BBC.
“It isn’t the geology — it’s just the type of construction. There are no quake-proof buildings. It’s mostly river stones held together with some sort of mortar — and mortar behaves awfully in earthquakes," admitted seismologist Lucy Jones, a visiting associate researcher at the California Institute of Technology.
In addition to the damage caused by earthquakes, landslides can also flatten houses in mountain villages and cause widespread flooding in Afghanistan. This hinders rescue operations by authorities, making the country's vulnerability to earthquakes even more challenging.
Why North India is prone to earthquakes?
The Himalayas, located in India's northern region, are the youngest mountains and were formed due to the movement of the Indian plate towards the Nepalese plate. This region is prone to frequent earthquakes due to its location on the boundary of two massive tectonic plates.
The government of India has identified nearly 59% of the country's land mass as prone to earthquakes of varying intensities. The country is divided into four seismic zones, with Zone V being the most active and Zone II being the least active.
Eight states and Union Territories, including the Delhi-NCR region, fall under Zone V, making them highly susceptible to earthquakes of the highest intensity.
Why did Tuesday's tremors feel so long in Delhi?
The reason why an earthquake in Afghanistan was felt in north India is due to the depth of the fault, J L Gautam, head of office and Scientist at National Center for Seismology, told Hindustan Times.
The earthquake's epicenter was over 150 km below the earth's surface, causing primary waves to be felt first, followed by secondary waves. Shock waves travel farther and last longer when the depth of the quake is greater, but their intensity is lower.
Hence, the earthquake in Afghanistan, with its epicenter 187.6 km below the earth's surface, could be felt across a larger distance with less intensity.
