Aftershocks Persist in Southern Tibet County Following Major Earthquake Impact

A powerful earthquake of magnitude 7.1 shook Dingri county near Mount Everest in southern Tibet on Tuesday. This event has led to 646 aftershocks, with at least 16 measuring over 3.8 in magnitude, according to officials. The Chinese authorities recorded the main quake at a magnitude of 6.8, resulting in 126 fatalities and 188 injuries.

Experts have noted that aftershocks are typical following a major earthquake in this seismically active Himalayan region. Here, the Indian tectonic plate collides with the Eurasian plate, forming extensive fault lines along the Tibetan plateau. The largest aftershock was recorded at a magnitude of 4.4.

Seismic Activity and Aftershocks

India's National Seismological Centre (NCS) reported that the main earthquake had a magnitude of 7.1. Since Tuesday, there have been at least 16 aftershocks of magnitude 3.8 or higher in the area. A preliminary analysis by NCS indicates that these earthquakes resulted from normal faulting at shallow depths in a North-South direction.

The region has experienced minor earthquakes over the past decade, suggesting pre-existing seismicity linked to ongoing tectonic processes. This history of activity is evident from the significant energy release near the epicentral zone, which caused moderate tremors as far away as Bihar.

Impact on Surrounding Areas

The earthquake's effects were felt across several states in eastern and northeastern India, including Bihar, Sikkim, Assam, and West Bengal, as well as neighbouring regions. Within two hours of the quake, residents from these states submitted more than 12 felt reports via the official website and mobile app.

A K Shukla, former head of NCS, remarked on the expected number of aftershocks, stating they could persist for days or even months. "We are not surprised by the number of aftershocks," Shukla said. "It is common; we had also seen it after the Kutch quake."

Historical Context and Geological Insights

The region near the India-Eurasia plate boundary has a history of large earthquakes. Over the past century, there have been ten earthquakes of magnitude 6 or greater within 250 km of Tuesday's quake, according to the US Geological Services.

This includes notable events like the 2015 Nepal earthquake with a magnitude of 7.3 and the 1934 earthquake with a magnitude of 8.0. The 2015 event was an aftershock of an earlier April 25 quake that year with a magnitude of 7.8.

Shukla explained that after a massive quake, residual stress is released through aftershocks as the ground settles from destruction below the surface. "The ground needs to be settled when there is destruction below," Shukla noted.