The 2015 Nepal earthquake (also referred to as the Himalayan earthquake) occurred at 11:56 NST on 25 April with a moment magnitude (Mw) of 7.8 or 8.1Ms and a maximum Mercalli Intensity of IX (Violent). Its epicenter was approximately 34 km (21 mi) east-southeast of Lamjung, Nepal, and its hypocenter was at a depth of approximately 15 km (9.3 mi).
It was the most powerful disaster to strike Nepal since the 1934 Nepal–Bihar earthquake. As of 28 April 2015, more than 5,000 people were believed to have died as a result, with casualties reported in Nepal and adjoining areas of India, China, and Bangladesh. Within minutes of the earthquake, the Government of India, via the Indian Armed Forces, initiated Operation Maitri (English: Operation Amity), a massive humanitarian mission with the primary objective of conducting relief and rescue operations in Nepal. The Indian government also evacuated Indian and foreign citizens from Nepal.
The earthquake triggered an avalanche on Mount Everest, killing at least 18. The death toll surpassed that of the 2014 Mount Everest avalanche, making it the most lethal day on the mountain. It triggered another huge avalanche in Langtang valley where 250 are missing. Centuries-old buildings were destroyed at UNESCO World Heritage sites in the Kathmandu Valley, including some at the Kathmandu Durbar Square, the Patan Durbar Square and the Bhaktapur Durbar Square. Nepal's government has declared three days of mourning after the quake.
Continued aftershocks occurred throughout Nepal, with one shock reaching a magnitude of 6.7 on 26 April at 12:54:08 NST.

The earthquake occurred on 25 April 2015 at 11:56am NST (06:11:26 UTC) at a depth of approximately 15 km (9.3 mi) (which is considered shallow and therefore more damaging than quakes that originate deeper in the ground), with its epicenter approximately 34 km (21 mi) east-southeast of Lamjung, Nepal, lasting approximately twenty seconds. The earthquake was initially reported as 7.5 Mw by the United States Geological Survey (USGS) before it was quickly upgraded to 7.9 Mw and finally downgraded to 7.8 Mw. The China Earthquake Networks Center (CENC) reported the earthquake's magnitude to be 8.1 Ms. The India Meteorological Department (IMD) said two powerful quakes were registered in Nepal at 06:11 UTC and 06:45 UTC. The first quake measured 7.9 Mw and its epicenter was identified at a distance of 80 km to the northwest of the capital Kathmandu. The second earthquake was somewhat less powerful at 6.6 Mw. The seismic focus lay at a depth of 10 km (6.2 mi) below the earth's surface. Bharatpur was the nearest major city to the main earthquake, 53 km (33 mi) from the epicenter. The second earthquake occurred 81 km (50 mi) northwest of Kathmandu, the capital of Nepal. Over thirty-five aftershocks of magnitude 4.5 Mw or greater occurred following the initial earthquake, including one of magnitude 6.6 Mw.
According to the USGS, the temblor was caused by a sudden thrust, or release of built-up stress, along the major fault line where the Indian Plate, carrying India, is slowly diving underneath the Eurasian Plate, carrying much of Europe and Asia. Kathmandu, situated on a block of crust approximately 120 km (75 miles) wide and 60 km (37 miles) long, reportedly shifted 3 m (10 ft) to the south in just 30 seconds.
The risk of a large earthquake was well known beforehand. In 2013, in an interview with seismologist Vinod Kumar Gaur, The Hindu quoted him as saying, "Calculations show that there is sufficient accumulated energy [in the MFT], now to produce an 8 magnitude earthquake. I cannot say when. It may not happen tomorrow, but it could possibly happen sometime this century, or wait longer to produce a much larger one." According to Brian Tucker, founder of a nonprofit organisation devoted to reducing casualties from natural disasters, some government officials had expressed confidence that such an earthquake would not occur again. Tucker recounted a conversation he had had with a government official in the 1990s who said, "We don't have to worry about earthquakes anymore, because we already had an earthquake;" the previous earthquake to which he referred was the one in 1934.

Nepal lies towards the southern limit of the diffuse collisional boundary where the Indian Plate underthrusts the Eurasian Plate, occupying the central sector of the Himalayan arc, nearly one third of the 2,400 km (1,500 mi) long Himalayas.