The 1977 San Juan earthquake was a major seismic movement that took place in the province of San Juan, Argentina, on 23 November 1977, at 09:26:23 AM. It measured magnitude 7.4 on the Richter scale. Its epicenter was at , and at a depth of 17 km. It was felt with grade IX in the Mercalli intensity scale.
The earthquake caused fatalities and severe damage to buildings throughout the province, especially in the city of Caucete, where 65 people died. It also caused slight damage in the north of the Greater Mendoza metropolitan area.