The Great Chilean Earthquake

On May 21, 1960, a tremor struck Valdivia, Chile, kicking off a series of quakes that would devastate the region. By the time it was over, 5,000 people had lost their lives and another 2 million were left homeless. The first quake measured 7.6 in magnitude and was deadly in its own right, but it turned out to be just a foreshock to one of the most powerful earthquakes ever recorded.

At 3:11pm the next afternoon, a massive magnitude 9.5 earthquake struck southern Chile, with its epicenter just off the coast beneath the Pacific Ocean. There, the Nazca oceanic plate plunged 50 feet under the South American plate. The quake triggered enormous landslides down the region’s mountains and unleashed a series of tsunamis along Chile’s coast. At 4:20pm, a 26-foot wave crashed ashore, sweeping away most buildings and structures as it receded. But the worst was yet to come…minutes later, a slower, towering 35-foot wave rolled in, killing an estimated 1,000 people, including many who had sought safety on higher ground. The 1960 Valdivia earthquake in Chile was the most powerful ever recorded. It caused widespread devastation, tsunamis, and significant global impact.

The Valdivia earthquake, also called the Great Chilean Earthquake, struck near Lumaco, about 354 miles south of Santiago, with Valdivia hit the hardest. Lasting around 10 minutes, it caused intense shaking and set off a series of tsunamis across the Pacific. This massive megathrust quake happened when the Nazca Plate was forced beneath the South American Plate along Chile’s coast. The fault shift stretched between 500 and 1,000 km, releasing immense energy and creating both vertical and horizontal ground movement. Foreshocks, including a magnitude 8.1 quake in Concepción the day before, had already caused major damage and hinted at the disaster to come. Cities like Valdivia and Puerto Montt suffered extensive destruction. Buildings collapsed, rivers changed course, and soil subsidence created new wetlands. Electricity and water systems were destroyed, and the city of Valdivia experienced severe flooding. Two days later, Cordón Caulle volcano erupted, marking the first eruption in four decades

The earthquake triggered tsunamis that swept across the Pacific, impacting far-off regions. In Hawaii, waves up to 35 feet hit Hilo, causing 61 deaths. Japan saw around 140 deaths and heavy property damage, while eastern New Zealand, southeast Australia, the Aleutian Islands, and parts of the United States West Coast suffered minor damage. In Chile, economic losses were estimated at $400 to $800 million at the time (about $4.5 to $8.8 billion today), with additional damages in Hawaii, Japan, and the Philippines from the tsunamis. The toll could have been much worse…thanks to a foreshock 30 minutes earlier, many people were already outside, avoiding building collapses, and the locals quickly evacuated the coast knowing that a tsunami was coming. After leaving Chile, the tsunami traveled hundreds of miles west toward Hawaii, the Philippines, and Japan, where hundreds also died. In fact, the waves set off by this earthquake bounced back and forth across the Pacific Ocean for a week. Aftershocks were recorded for a full 30 days after the main tremor.