The 1970 Ancash earthquake or Great Peruvian earthquake occurred on May 31 off the coast of Peru in the Pacific Ocean. Combined with a resultant landslide, it was the worst catastrophic natural disaster ever recorded in the history of Peru. Due to the large amounts of snow and ice included in the landslide and its estimated 54,000 to 74,000 casualties, it is also considered to be the world's deadliest avalanche.
The earthquake struck on a Sunday afternoon at 15:23:31 local time (20:23:31 UTC) and lasted 45 seconds. The quake destabilized the northern wall of Mount Huascarán, causing a rock, ice and snow avalanche and burying the towns of Yungay and Ranrahirca. The avalanche started as a sliding mass of glacial ice and rock about 3,000 feet (910 m) wide and one mile (1.6 km) long. It advanced about 11 miles (18 km) to the village of Yungay at an average speed of 280 to 335 km per hour. The fast-moving mass picked up glacial deposits and by the time it reached Yungay, it is estimated to have consisted of about 80 million cubic meters (80,000,000 m³) of water, mud, and rocks.
Yungay Viejo (2500 m) as seen from the cemetery hill. The light shaded area shows the location of the landslide (ice, mud, debris avalanche) on 31.05.1970, caused by an earthquake, in which a part of the western flank of Huascaran Norte broke (6652 m). Yungay Nuevo is behind the shaded area in the center.
^ abcdUtsu, T. R. (2002), "A List of Deadly Earthquakes in the World: 1500-2000", International Handbook of Earthquake & Engineering Seismology, Part A, Volume 81A (First ed.), Academic Press, p. 708, ISBN978-0124406520