New Delhi: On January 7, 2025, a powerful earthquake of 7.1 magnitude struck the mountainous region in western China near the Nepal border. It has killed at least 53 people and injured a minimum of 68 people, apart from extensively damaging buildings and infrastructure. According to the US Geological Survey (USGS), the earthquake’s epicentre was 93 kilometres northeast of Nepal’s Lobuche near the border with Tibet. Tremors have also been felt in Nepal, Uttar Pradesh, Bihar, Delhi-NCR and some northeastern states. Normally, earthquakes are associated with aftershocks and in this article, we will learn about it and why does it take place.
What is an aftershock?
An aftershock is defined in seismology as a smaller earthquake which comes after a larger earthquake. It affects the same area of the main shock and takes place as the displaced crust adjusts to the main shock’s effects. If the earthquake is large, then it can have hundreds to thousands of aftershocks which can be detected in the instruments. The aftershocks decrease steadily in magnitude and frequency following a consistent pattern. In some earthquakes, the main rupture takes place in two or more steps which result in multiple main shocks known as doublet earthquakes and they are different from aftershocks.
Why do aftershocks take place?
After main earthquake or the main shock, the aftershocks take place as the lower-magnitude tremors. During the occurrence of an earthquake, some energy released from the rock’s sudden fracturing is transferred to nearby rocks, which adds to the pushing, pulling, and twisting stresses placed on them.
When the rocks cannot bear the stresses any longer, they break and release a new round of energy, which create new faults in the rock. Thus, earthquakes produce aftershocks and those in turn result in smaller and smaller aftershocks. In the hours and days that follow an earthquake, the aftershocks tend to be most severe and frequent. Over time, their magnitude and frequency decrease. Generally, aftershocks are found up to a distance equal to the rupture length away from the fault plane.
What are the effects of aftershocks?
Aftershocks are usually unpredictable which makes them dangerous. They can be of large magnitude and can led to the collapse of buildings already damaged by the main shock. The bigger the earthquake, the more aftershocks it will have and they can last for a long time. Also, aftershocks can be stressful for people coping with the damage and loss of life caused by the main quake.
A 7.1 magnitude earthquake struck near the Nepal-China border on January 7, 2025, causing significant devastation. This article explores the phenomenon of aftershocks, explaining their causes, the readjustment of the Earth’s crust after a major earthquake, and their potentially devastating effects. knowledge Knowledge News, Photos and Videos on General Knowledge
