March 19, 1971 Tsunami: Chungar, Peru

Chungar Rock Avalanche and Resulting Displacement Wave, 1971. In March 1971, a catastrophic wave of water formed by a high velocity rock avalanche struck the camp of the Chungar Mining Company on the shore of Lake Yanahuin in the Province and Department of Pasco in the Peruvian Andes, killing an estimated 400-600 people and destroying all but a few of the surface facilities of the mine (Plafker and Eyzaguirre, 1979). The rock avalanche (estimated volume: 100,000 m3) fell from an outcrop of jointed limestone situated about 400 m above the lake. Water displaced by the rock mass formed a wave that inundated the opposite shore of the lake to a height of 30 m, devastating almost all of the mining camp except for two concrete-block bunkhouses. In addition, water poured into a mineshaft, drowning several miners. (reference #10819)

Sr. Acasio Baldon Pablo, a resident at Yanahuin Lake for seventeen years, witnessed the avalanche. He described the fall as comparable to a "breaking wall" and the sound made by the avalanche as a roar "like an explosion". He said that individual rocks occasionally fell from the avalanche source for about a year previously and that some of them rolled down the steep talus slope and splashed into the lake […] Initial news reports in the United States incorrectly attributed triggering of the Chungar avalanche to an earthquake (Smithsonian Institution for Short-Lived Phenomena Reports, 22 March 1971 and 6 April 1971). However, survivor accounts and seismographic data from the Huancayo station, 150 km to the southeast, indicate that there was no local earthquake at the time of the disaster nor had there been noteworthy felt earthquakes in the area at any time during the preceding months. (reference #10823)