THEY SAID THE DEPTH OF THE FAULT IS OVER 150 KM. AT FIRST,THE PRIMARY WAVES WERE FELT AND THEN SECONDARY WAVES.
On 21st March 2023, Afghanistan became the epicenter of the powerful 6.6-magnitude earthquake. The shocks were also felt by the people in Delhi-NCR. Many were forced to escape their homes for safety as a result of the tremors. On Twitter, people shared videos and footage of their shaking household items while others sought to clarify what they had just felt. While some Twitter users were horrified, others used the unfortunate circumstance to create some humorous memes.The hashtag #earthquake quickly started trending last night and around 10,000 tweets have been posted using the same. A health ministry official in Afghanistan reported that at least four people were killed and fifty injured. The United States Geological Survey (USGS) reported on Tuesday that the earthquake’s epicenter was located 40 kilometers (25 miles) southeast of the Afghan town of Jurm, close to the borders with Pakistan and Tajikistan. Over 285 million people in Uzbekistan, Pakistan, India, Tajikistan, Kazakhstan, Afghanistan, Kyrgyzstan, and Turkmenistan felt the tremor, over a region more than 1,000 km (621 miles) wide. While most of the tragic news is coming from Pakistan, Twitter users in India have been circulating videos of lightning in the sky. Several reactions were shared such as, “It was a massive earthquake. With two kids that too on 18th floor it was scary. Came down by stairs,” said a user. “Stay safe everyone and recite this and pray for everyone’s safety. #earthquake,” said another. “Social media managers on their duty of creating posts to confirm everyone about the #earthquake in Delhi,” joked a third.
How big is the earthquake?
How much damage an earthquake will cause depends on its depth and magnitude.
Shallow earthquakes are generally more devastating because they carry greater energy when they emerge on the surface. Deeper earthquakes lose much of their energy by the time they come to the surface. The deeper quakes spread farther — the seismic waves move radially upwards to the surface — even as they lose energy while travelling greater distances, and hence cause less damage. Thus, the current tremors are unlikely to cause much damage in India.
This earthquake was of 6.5-magnitude. The earthquake magnitude scale gives a measure of the energy released, although the reading in itself is not of energy. Rather, it takes into account amplitude or ‘size’ of the seismic waves released, and variations in distance between various seismographs and the earthquake epicentre. Thus, it is a dimensionless number — with no physical units.
While it used to be measured on the Richter ccale, nowadays, the ‘moment magnitude scale’ is used as it is more accurate for bigger quakes. Both scales are logarithmic – which means the seismic waves produced by a magnitude 6 earthquake have 10 times higher amplitude than the ones produced by a magnitude 5 earthquake. The energy differential is even higher, 32 times (31.623 or 10 raised to the power 1.5 to be precise), for every change of 1 in magnitude.
Tremors lasting several seconds were felt in Delhi and other parts of North India as a strong 6.5-magnitude earthquake struck Afghanistan on Tuesday night, the US Geological Survey (USGS) said.
The earthquake was deep, with its origin 187.6 km below the earth’s surface, the USGS said. Deep earthquakes tend to be felt over large distances, which is why tremors were experienced in Punjab, Rajasthan’s Jaipur, and Jammu and Kashmir.
The epicentre of the earthquake was near Jurm in northeastern Afghanistan, about 300 km north of Kabul, quite close to Afghanistan’s borders with Tajikistan, according to the USGS. This is an earthquake-prone region where six-plus earthquakes are not rare. A similar 6.1 magnitude earthquake had occurred very close to this place in 2018 as well, which again was felt through most of northern India.
