The moment magnitude (Mw ) 7.4–7.6 earthquake killed 400–500 people and inflicted US$1 billion (adjusted for inflation) in damage.

[1][2] 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.

On 22 March 1965, a magnitude 6.2–6.4 earthquake rocked the coastal town of Los Vilos at a depth of 48.8 kilometers (30.3 miles), slightly north of the epicenter of the mainshock.

The focal mechanism of this earthquake suggests normal faulting within the slab of the Nazca plate rather than on the subduction zone interface of the megathrust.

The Department of Illapel reported more than 90% of homes had been damaged, and a hospital was completely destroyed, adding that "only facades of the houses remain standing".

Four persons died from the temblor, including a woman who fell to her death after jumping off the second floor of a hospital and another during a stampede to race for the exit at a racetrack after a grandstand collapsed, while ten were injured.

Additional casualties were reported at Llay-Llay, where four people had died, two each in La Laguna and Quilpué, and one each in San Felipe, Colina, Melon, Olmué and Ventanas.

The Ministers of Public Works and Defence were taken to the affected town of Llay-Llay to survey the damage extent and plan the rescue and recovery efforts.

[12] This tragedy, along with the 1960 earthquakes, was one of the reasons for the formation of the National Office of Emergency of the Interior Ministry which oversees natural disasters and rescue efforts in Chile.

Prior to the disaster, there had not been any formal organization to coordinate any rescue and recovery efforts, mainly because local officials and residents have endured many of the frequent earthquakes in the area.