Seismic Challenges In Nepal

Nepal lies in the central part of the geologically young Hindu-Kush-Himalaya region, which is the result of the collision between the Indian and Eurasian tectonic plates. This region is known for its high seismic activity, making it one of the most seismic-prone zones. The primary cause of frequent earthquakes in Nepal is the subduction of the Indian plate below the Eurasian plate, which links up converging forces along the plate boundary and results in regular earthquakes. Avouac (2003) mentioned that the subduction of the Indian continent beneath the Tibetan Plate occurs at a rate of approximately 20 mm per year. Hubbard et al. (2016) noted the geological features in Nepal, such as faults and thrusts, trigger earthquakes. 

Nepal has a long history of devastating earthquakes, with many significant seismic events recorded throughout the centuries. In his article, "A Step Towards Historical Seismicity of Nepal," Mahes Raj Pant mentions that the earliest recorded earthquake took place on December 24, 1223, according to 14th-century chronicles found in the Gopalarajavamsavali manuscript. 

On the other hand, Brahma Shumsher Jung Bahadur Rana's book "Nepal Ko Mahabhukampa 1990" states that the first recorded earthquake happened on June 7, 1255 A.D., which resulted in widespread destruction. This included the loss of nearly one-third of the population in the Kathmandu Valley, including King Abhaya Malla. Based on past research, significant earthquakes occurred in Nepal in the years 1260 A.D., 1344 A.D., 1408 A.D., 1505 A.D., 1681 A.D., 1810 A.D., 1823 A.D., 1833 A.D., 1934 A.D., 1980 A.D., 1988 A.D., 2011 A.D., 2015 A.D., 2022 A.D., and 2023 A.D.

Among the historic earthquakes, the 1934 Nepal-Bihar Earthquake, the 1988 Udaypur Earthquake, and the 2015 Gorkha Earthquake are significant in the study of Nepal’s seismicity. On January 15, 1934, the most severe earthquake in modern times with a magnitude of 8.4 struck the eastern mountains of Nepal. According to Brahma Shumsher J.B.R., this earthquake resulted in 8,519 casualties and caused extensive structural damage. The Udaypur Earthquake, with a magnitude of 6.8, struck eastern and central Nepal, including the Kathmandu Valley, on August 21, 1988. According to the Building Code Development Project (BCDP), 1994, this earthquake caused 721 deaths, 12,244 injuries, and damaged nearly 66,000 buildings. The 2015 Gorkha Earthquake occurred on April 25, 2015, with a main shock of a magnitude of 7.8 followed by a strong aftershock of a magnitude of 6.7 the same day. 

On April 26, 2015, another aftershock of magnitude 6.9 struck central Nepal, and the strongest aftershock with a magnitude of 7.3 occurred on May 12, 2015. The National Planning Commission (NPC), 2015: Post-Disaster Needs Assessment, reports that the earthquake caused 8,790 deaths and more than 22,300 injuries. Assessments showed that at least 498,852 private houses and 2,656 government buildings were destroyed. Moreover, 256,697 private houses and 3,622 government buildings were partially damaged. In addition, 19,000 classrooms were destroyed and 11,000 damaged.

In recent years, Nepal experienced three significant earthquakes impacting the western region. On November 9, 2022, a 6.6 local magnitude earthquake hit Doti. This caused the death of 6 people and injured many. 4,646 houses were fully damaged, and 10,911 houses were partially damaged in the Doti, Achham, Bajura, Bajhang, and Dadeldhura districts. On October 3, 2023, the Bajhang District was hit by a series of earthquakes. The foreshock, with a local magnitude of 5.3, struck, followed by an earthquake of local magnitude 6.3 and an aftershock with a local magnitude of 5.1 occurred. 

These triggered a landslide claiming a life and many injuries. This caused significant damage to various private, public, and government structures. On November 3, 2023, a 6.4 local magnitude earthquake hit Jajarkot and Rukum West, affecting 11 other districts. This resulted in the death of 154 people, with 366 injuries. The initial assessment reported that 62,012 private houses, 626 school buildings, and 50 government buildings were either destroyed or partially damaged. The detailed damage assessment is yet to be done for these three earthquakes.

In the entire Himalayas, especially in Nepal, earthquakes occur and are recorded regularly.The National Earthquake Monitoring and Research Centre (NEMRC) database has recorded 1,237 earthquakes with a local magnitude of 4 or higher from 1994 to now. West Nepal has been identified as a seismic gap, meaning it hasn't experienced significant earthquakes for over 500 years. This raises concerns about the possibility of a large earthquake occurring soon. One of the most significant earthquakes in history was the 1505 Lo Mustang earthquake, which occurred on June 6, 1505, and had an estimated magnitude of 8.2.Since that time, no major earthquake of similar size has occurred in this region, but other areas remain vulnerable due to continued seismic activity. 

Since December 2024, Nepal has recorded 11 earthquakes with magnitudes over 4, emphasising the critical need for better resilience and preparedness. Many lessons from the Gorkha Earthquake have not yet been implemented. To reduce future risks, the federal government must ensure that the Nepal National Building Code is enforced throughout the country. 

Given that rural areas largely use adobe, round stones, and mud mortar for construction, emphasis should be placed on strengthening techniques for these structures. Vulnerable buildings, including schools, hospitals, and heritage sites, require seismic retrofitting.

 Funding should be allocated for seismic hazard mapping and establishing an earthquake early warning system. Until such a system is operational, coordinating with modern platforms like the Android Earthquake Alerts System, which provide timely alerts, is a must. Adequate research and disaster preparedness education for students, regular mock drill exercises training, and capacity building of architects, engineers, and construction workers should be performed at the local level. Laws, rules, and regulations should be made up-to-date on the basis of lessons from the past. To minimise the economic impacts of disasters, the government should adopt risk financing measures and establish collective insurance plans.


(Er. Paudel is a civil engineer with a specialisation in structural earthquake engineering.)