Chile earthquake of 1960, the largest earthquake recorded in the 20th century. Originating off the coast of southern Chile on May 22, 1960, the temblor caused substantial damage and loss of life both in that country and—as a result of the tsunamis that it generated—in distant Pacific coastal areas.

Chile earthquake of 1960 Homes in Valdivia, Chile, destroyed by the earthquake of 1960. Pierre St. Amand/National Geophysical Data Center/NOAA

Chile earthquake of 1960 Newsreel describing the Chile earthquake of 1960. Universal Studios See all videos for this article

The earthquake hit at 3:11 pm approximately 100 miles (160 km) off the coast of Chile, parallel to the city of Valdivia. The shock is generally agreed to have had a magnitude of 9.5, though some studies alternately proposed that it may have been 9.4 or 9.6. A series of foreshocks the previous day had warned of the incipient disaster; one, of magnitude 8.1, caused major destruction in Concepción. The fault-displacement source of the earthquake extended over an estimated 560–620 mile (900–1,000 km) stretch of the Nazca Plate, which subducted under the South American Plate. As the quake occurred just prior to a revolution in seismologic technology in the 1960s, these figures are based mainly on post hoc analysis.

Chile earthquake of 1960 Map depicting the epicentre of the earthquake off the coast of Chile, May 22, 1960. Encyclopædia Britannica, Inc.

Many Chilean cities sustained significant damage, including Puerto Montt, where noticeable subsidence occurred, and Valdivia, where nearly half of the buildings were rendered uninhabitable. Though the havoc wreaked by the shaking was not inconsequential, most casualties resulted from the descent 15 minutes later of a tsunami that rose up to 80 feet (25 metres) high on the expanse of Chilean coastline—bounded by the cities of Lebu and Puerto Aisen—that paralleled the subducting plate. The combined effects of the disaster left two million people homeless. Though the death toll was never fully resolved, early estimates ranging into the thousands were scaled back to 1,655. About 3,000 people were injured.

Chile earthquake of 1960: tsunami Map showing the extent of the tsunami generated by the Chile earthquake of 1960. Encyclopædia Britannica, Inc.

Castro, Chiloé Island after the Chile earthquake of 1960 Buildings damaged by earthquake and fire, Castro, Chiloé Island, after the Chile earthquake of May 22, 1960. Pierre St. Amand/National Geophysical Data Center/NOAA

The enormity of the seafloor shifts that caused the tsunamis was such that the waves that arrived nearly 15 hours later in the Hawaiian Islands—6,200 miles (10,000 km) away—still crested at nearly 35 feet (11 metres) at landfall in some places. The waves caused millions of dollars of damage at Hilo Bay on the main island of Hawaii, where they also killed 61 people. When they reached the main Japanese island of Honshu 22 hours after their generation, the waves had subsided to about 18 feet (5.5 metres) and laid waste to over 1,600 homes and killed 138 people. In the Philippines, tsunami waves left 32 dead or missing. Though the oblique angle by which the waves approached the Pacific coast of the United States mitigated their force, Crescent City, California, saw waves of up to 5.6 feet (1.7 metres), and boats and docks in Los Angeles, San Diego, and Long Beach were damaged.

tsunami damage in Hilo, Hawaii after the Chile earthquake of 1960 Debris from buildings damaged by a nearly 35-foot (11-metre) tsunami, Hilo, Hawaii island, Hawaii. The force of the wave—caused by an earthquake on May 22, 1960, off the coast of Chile—was enough to bend parking meters to the ground. Sunset Newspaper/National Geophysical Data Center/NOAA

tsunami damage in Hilo, Hawaii after the Chile earthquake of 1960 Cleanup operations commencing in Hilo, Hawaii island, Hawaii, following the tsunami caused by the May 22, 1960, earthquake off the coast of Chile. Pacific Tide Party/National Geophysical Data Center/NOAA

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Two days later the Cordón Caulle volcano in Chile’s Lake District erupted after nearly 40 years of inactivity, an event thought by some seismologists to be linked to the quake.