An Mw  7.4 earthquake in Chile sets off a series of tailings dam failures, burying the town of El Cobre and killing at least 500 people.

The 1965 La Ligua earthquake struck near La Ligua in Aconcagua Province, Chile, about 140 km (87 mi) from the capital Santiago on Sunday, March 28 at 12:33 local time. The moment magnitude (M_w ) 7.4–7.6 earthquake killed 400–500 people and inflicted US$1 billion in damage. Many deaths were from El Cobre, a mining location that was wiped out after a series of dam failures caused by the earthquake spilled mineral waste onto the area, burying hundreds of residents. The shock was felt throughout the country and along the Atlantic coast of Argentina.

A tailings dam is typically an earth-fill embankment dam used to store byproducts of mining operations after separating the ore from the gangue. Tailings can be liquid, solid, or a slurry of fine particles, and are usually highly toxic and potentially radioactive. Solid tailings are often used as part of the structure itself.

March 28 is the 87th day of the year in the Gregorian calendar; 278 days remain until the end of the year.