Tectonic Hazards

An earthquake is a physical event, but the scale of the disaster also depends on the people and buildings exposed to it and their ability to cope. Nepal had limited financial resources, and in 2015 about 80% of its population lived in rural communities, many of them remote. This made reaching survivors and supplying aid difficult.

Why the earthquake happened

Nepal lies at a collision boundary between the Indian and Eurasian plates. As the plates move towards one another, the crust is compressed. Movement is not always smooth: friction can prevent rocks from moving while stress builds. When rocks suddenly slip along a fault, stored energy is released as seismic waves, causing the ground to shake.

The earthquake began at a shallow focus, approximately 15 km beneath the surface. A shallow focus means that seismic waves travel a relatively short distance before reaching the surface, helping explain the damaging shaking. More than 300 aftershocks followed, creating further danger for survivors and rescuers.

Plate movement explains why the earthquake occurred. It does not, on its own, explain the death toll. Building vulnerability also mattered: the Dharahara Tower in Kathmandu, which had not been retrofitted to improve its earthquake resistance, collapsed.

Direct damage to people and services

Primary effects resulted directly from the shaking. Buildings collapsed, killing and injuring people and leaving almost 3.5 million people homeless. Approximately 7,000 schools and 1,000 health facilities were damaged or destroyed. Electricity and water supplies were cut.

These losses affected more than buildings. Damaged health facilities reduced access to treatment when large numbers of people needed medical help. Damage to schools disrupted education, while the destruction of offices, shops and factories prevented people from earning a living.

Many temples and UNESCO World Heritage sites were also destroyed. This was both a cultural loss and an economic problem because Nepal relied on income from tourism.

How the effects spread through the landscape and economy

Secondary effects were triggered by the earthquake or developed from its initial damage. Shaking triggered avalanches on Mount Everest and in the Langtang Valley, as well as landslides that blocked roads and rivers.

Blocked roads made an already difficult relief operation harder: supplies and rescue teams could not easily reach isolated communities. The combination of damaged tourist attractions and disruption to mountain tourism reduced tourist income, affecting livelihoods beyond the places where buildings had collapsed.

Damage was estimated at US$7–10 billion, around 35% of Nepal's GDP. GDP measures the value of goods and services produced in a country in a year. This comparison shows the enormous scale of the damage relative to Nepal's economy, helping explain why international assistance was important.

Immediate responses: saving lives and meeting basic needs

The first priority was to find survivors, treat injuries and provide shelter and supplies. Around 90% of the Nepalese army was mobilised. Other countries sent search-and-rescue teams, medical staff, medicines, food, water, clothing and temporary shelters.

Tent cities in Kathmandu provided temporary accommodation for people whose homes were unsafe or destroyed. A GIS crisis-mapping tool helped coordinate the response by organising location-based information. This supported decisions about where assistance was needed.

The Asian Development Bank provided a US$3 million emergency relief grant. Emergency relief addressed urgent needs; it could not replace all the homes, services and livelihoods that had been lost.

Long-term responses: rebuilding and reducing future harm

Recovery involved restoring access and essential services. Landslides were cleared and roads repaired so that remote rural communities could be reached again. Schools were rebuilt, and the Asian Development Bank provided US$200 million for rebuilding.

Other responses aimed to reduce the consequences of future earthquakes. Stricter building codes and stronger enforcement sought to improve building safety. Earthquake drills taught people what to do during an earthquake, and a new government task force was established to plan for future events.

These measures could not stop the Indian and Eurasian plates moving. Their purpose was to make people and buildings less vulnerable. Nepal therefore illustrates the connection between a physical hazard, social and economic vulnerability, emergency relief and longer-term risk reduction.