Monday 6 November 2023

At least 157 people dead following Magnitude 5.7 Earthquake in Jajarkot District, Nepal.

The United States Geological Survey recorded a Magnitude 5.7 Earthquake at a depth of 16.5 km, in Jajarkot District, Nepal slightly after 11.45 pm local time, (slightly after 6.00 pm GMT) on Friday 3 November 2023. At the time of writing 157 people have been confirmed dead following the event, and 184 injured, with many more made homeless as large numbers of mud-brick buildings collapsed in the region. Such buildings are particularly vulnerable to Earthquakes as the bricks often liquefy, trapping people inside and quickly asphyxiating them with dust. This is particularly dangerous at night when the majority of people are inside sleeping.

Damage caused by an Earthquake in the west of Nepal on 3 November 2023. EPA/EFA/Rex/Shutterstock.

Earthquake activity in Nepal is caused by the uplift of the Tibetan Plateau, due to the impact of India into Eurasia to the south. The Indian Plate is moving northwards at a rate of 5 cm per year, causing it to impact into Eurasia, which is also moving northward, but only at a rate of 2 cm per year. The collision of the Indian and Eurasian plates has led to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

Block diagram showing how the impact of the Indian Plate into Eurasia is causing uplift on the Tibetan Plateau. Jayne Doucette/Woods Hole Oceanographic Institution.

Much of northern India and neighbouring areas of Central Asia and the Himalayas, are prone to Earthquakes, caused by the impact of the Indian Plate into Eurasia from the south. When two tectonic plates collide in this way and one or both are oceanic then one will be subducted beneath the other (if one of the plates is continental then the other will be subducted), but if both plates are continental then subduction will not fully occur, but instead the plates will crumple, leading to folding and uplift (and quite a lot of Earthquakes). The collision of the Indian and Eurasian plates has led to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

The movement of India into Eurasia over the last 71 million years. USGS.

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