What is earthquake? Why Delhi-NCR region is vulnerable to earthquakes?

Delhi-National Capital Region has felt two earthquakes this week. The epicentre of both was located in Nepal. However, because to its location in a seismically active region, scientists have repeatedly warned that Delhi might experience devastating earthquakes. Delhi-NCR 's high population density and abundance of high-rises increase the dangers of a major disaster in an earthquake.

About 295 years ago, Delhi saw the last major earthquake to have its epicentre in the city. Despite experiencing tremors and some damage in the past when massive earthquakes struck the regions around the Himalayas, the city was mostly spared from widespread destruction. 

What is an earthquake?

The term 'earthquake' refers to the violent shaking of the Earth's surface. The trembling originates from the outermost layer of the Earth moving. Although the Earth seems to be a stable planet from space, it is really rather dynamic under the surface.

When two blocks of the earth abruptly slide past one another, it causes an earthquake. They slide along a surface known as a fault or fault plane. The hypocenter is the point below the surface of the Earth where the earthquake begins, while the epicentre is the point immediately above it on the surface.

Why Delhi-NCR region is vulnerable to earthquakes?

Delhi is situated on the Sohna fault line, the Mathura fault line, and the Delhi-Moradabad fault line, all of which are active seismic fault lines. Gurgaon, however, is the most dangerous part of the Delhi–National Capital Region since it is situated on no less than seven fault lines.

Using a macro seismic zoning map, the Bureau of Indian Standards divided the whole nation into four distinct categories, ranging in severity from Zone V (high intensity) to Zone II (low intensity) (low intensity). Zone IV includes the Delhi-Mumbai-Area. The seismic activity of Zone II is the lowest, while that of Zone V is the highest. The "severe" and "extremely severe" designations apply to Zones IV and V, respectively.

Also, READ: Earthquake in Delhi-NCR rock Twitter, users share memes, scary videos

Most vulnerable places in Delhi-NCR region

According to a research on the "seismic hazard microzonation" of Delhi published by the Ministry of Earth Sciences, areas along the Yamuna and its flood plain, including densely populated residential complexes in east Delhi, would be among the hardest impacted during an earthquake. The Lutyens' zone, home to the Indian Parliament, the major ministries, and the residences of India's most prominent citizens, is also in the high danger zone, albeit it is not as as at risk as the districts along the Yamuna.