The epicentre of the earthquake was under the Pacific Ocean, about 15 miles (25 km) west of the Peruvian fishing port of Chimbote, in the Ancash department of north-central Peru. It occurred at about 3:20 PM local time and had a moment magnitude of 7.9. The effects of the quake could be felt from the northern city of Chiclayo south to the capital city of Lima, a distance of more than 400 miles (650 km). The most damage occurred in the coastal towns near the epicentre and in the Santa River valley. The destruction was exacerbated by the construction techniques used in the area; many homes and buildings were constructed using adobe, with many built on unstable soil.

Tens of thousands of people were killed or injured when their homes or businesses collapsed, and a significant number of victims died as the result of landslides triggered by the quake. The most destructive landslide fell from Peru's highest mountain, Mount Huascarán (Huascarán, Mount), located in the west-central Andes. Fast-moving snow and earth swallowed the village of Yungay, buried much of Ranrahirca, and devastated other villages in the area.