Produced by: Tarun Mishra
Designed by: Mohsin Shaikh
On Tuesday, a series of four earthquakes struck Nepal, with the most powerful registering a magnitude of 6.2. Tremors were also felt in various parts of North India, including Delhi-NCR
According to the National Centre for Seismology (NCS), the sequence of seismic events unfolded with the initial shock of a magnitude 4.6 earthquake occurring in western Nepal at 2:25 pm. Following this, a significant 6.2 magnitude tremor occurred at 2:51 pm
Two more earthquakes, measuring 3.6 and 3.1 on the Richter scale, struck the same region at depths of 15 km and 10 km at 3:06 pm and 3:19 pm, respectively
The epicenter of the strongest earthquake was pinpointed in the Dipayal district of western Nepal. It is located 206 km southeast of Joshimath in Uttarakhand and 284 km north of Lucknow, the capital of Uttar Pradesh
The seismic activity was meticulously recorded by more than 60 broadband seismic stations deployed by the National Centre for Seismology. An in-depth analysis of the collected data indicates that these events transpired along the North Almora Thrust (NAT), underscoring notable structural heterogeneity in the surrounding geological landscape. Preliminary assessments from fault plane solutions suggest that a thrust fault mechanism was responsible for these tremors
Within a span of just one hour, the NCS received over 70 reports from individuals in various locations. These reports originated from Delhi, Uttarakhand, Uttar Pradesh, Bihar, Himachal Pradesh, Rajasthan, and Punjab, providing invaluable information regarding the perceived intensities. The Modified Mercalli Intensity (MMI) Scale was employed to categorise the intensities, ranging from I to III
The National Centre for Seismology pointed out that three notable earthquakes had previously occurred within a 50 km radius of the location of Tuesday's tremors. These prior events took place on November 9, 2022 (magnitude 6.3), January 24 (magnitude 5.8), and February 22 (magnitude 4.4). Importantly, these earlier earthquakes had also reverberated through Delhi-NCR and neighbouring states
Earthquakes in the region are primarily attributed to the complex tectonic settings of the Himalayas. These settings encompass the Himalayan Frontal Thrust (HFT), Main Boundary Thrust (MBT), Main Central Thrust (MCT), as well as several local faults and geological lineaments, contributing to the seismic activity
The states in India that felt the tremors fall under seismic hazard zones V and IV, as classified by the National Centre for Seismology, indicating the regions' susceptibility to seismic events
Nepal, situated in one of the world's most active tectonic zones (seismic zone IV and V), remains highly susceptible to earthquakes. The country tragically experienced a devastating 7.8 magnitude earthquake on April 25, 2015, resulting in the loss of more than 8,000 lives and injuries to over 21,000 people