A sequence of three major earthquakes struck central Chile on 21–22 May 1960, forming the foreshock sequence for the largest recorded earthquake in history.
Key Facts
- First earthquake magnitude
- 8.1–8.3 Mw
- Duration of first earthquake
- 35 seconds
- Buildings destroyed in Concepción
- One third
- Second earthquake magnitude
- 7.1 Mw
- Third earthquake magnitude
- 7.8 Mw / MS
- Time before Valdivia earthquake
- 15 minutes
By the Numbers
Location
Cause → Event → Consequence
Intense seismic activity along the subduction zone off the coast of south-central Chile generated a rapid succession of large ruptures. The region sits above one of the world's most tectonically active plate boundaries, making it prone to major earthquakes, and this sequence represented the build-up of stress that would culminate in the 1960 Valdivia earthquake.
Between 21 and 22 May 1960, three destructive earthquakes struck south-central Chile in quick succession. The first, magnitude 8.1–8.3 Mw, struck near Cañete at 06:02 UTC-4 on 21 May, destroying a third of Concepción's buildings. A 7.1 Mw event followed on 22 May near Nahuelbuta National Park, accompanied by a 6.8 Mw aftershock. A third earthquake of 7.8 magnitude struck near Purén later that day.
The earthquakes caused widespread destruction across Concepción and surrounding areas, and disrupted a coal miners' march on the city. Occurring as foreshocks to the 1960 Valdivia earthquake—the largest instrumentally recorded earthquake in history, which struck just 15 minutes after the third event—they compounded the catastrophic impact on the region.