Surviving a Tsunami: Lessons From the 1960 Chile Disaster in Chile, Hawaii and Japan

On May 22, 1960, the largest earthquake ever measured, magnitude 9.5, struck the coast of southern Chile. Along a stretch of coast 600 miles long and more than 100 miles wide, the edge of the South American Plate lurched as much as 60 feet over the Nazca Plate diving beneath it, and the sea floor heaved. The tsunami that followed, a train of waves rather than a single one, killed people in Chile within minutes, reached Hawaii in 15 hours and Japan in 22. In Chile the earthquake and tsunami together took more than 2,000 lives and left an estimated 1 million people temporarily homeless; the tsunami killed 61 people in Hawaii and 138 in Japan.

Decades later, in the 1980s and 1990s, researchers interviewed survivors in all three countries. The U.S. Geological Survey gathered their stories into a booklet for anyone who lives, works or plays on a coast a tsunami could reach, including Cascadia (southern British Columbia, Washington, Oregon and northern California), whose own subduction zone set off a tsunami in 1700 that struck Japan with waves about as big as those of 1960. Some of the stories show what reliably saves lives. Others show desperate measures that worked for some and failed for others.

The earthquake may not be what kills you

José Argomedo, 22, was riding his horse outside Maullín, Chile, when the ground shook hard for several minutes. It was the height of the Cold War, and he thought it had turned hot. Everyone in and around Maullín survived the shaking, the biggest ever measured. But 122 people in the area were killed by the tsunami that followed.

Lesson: in coastal areas, the tsunami after a great subduction-zone earthquake may kill more people than the earthquake itself. Surviving the shaking is only the first step.

Heed natural warnings

The shaking itself is a warning, and so is a sudden fall or rise of the sea.

In Queule, Chile, a mile from the sea, many people headed for the hills soon after the quake; going to high ground probably saved hundreds of lives. Jovita Riquelme's family stayed in their house on low ground by the river. The tsunami caught them there: her husband was badly injured and died, and her 5-year-old daughter's body was found three days later. Most of Queule was washed away, with water as deep as 13 feet.

Near Mehuín, a man on horseback told Vitalia Llanquimán that the sea had drawn back from the shore. She was not alarmed, but her husband took it as a sign that the sea would come surging back. Carrying their two youngest children, they climbed a nearby hill and stayed there, safe, through the tsunami.

Heed official warnings, and don't come back too soon

In Hilo, Hawaii, there was plenty of time. At 6:47 p.m. the U.S. Coast and Geodetic Survey warned that waves would arrive around midnight, and at about 8:30 p.m. the sirens sounded. But people read the sirens differently: only about a third took them as a signal to leave at once, and several earlier alerts had been followed by harmless waves.

The first wave, only a few feet high, came just after midnight. Hearing that the waves were small and the danger over, 16-year-old Carol Brown and her brother returned to town. Around 1 a.m. they heard a low rumbling, then crashing, and a wall of water floated their house off its foundation. They survived; 61 other people in Hilo died and 282 were badly hurt.

Expect many waves: the next may be bigger

A USGS seismologist, Jerry Eaton, and four companions drove from the Hawaiian Volcano Observatory to Hilo to measure the tsunami from the Wailuku River bridge, having first planned their own sprint to high ground. The first wave raised the water 4 feet; the second, 9 feet; then the water fell to 7 feet below normal. Out in the dark bay came a rumble like a distant train, then a pale wall of tumbling water. At 1:04 a.m. the men ran, and turned to watch a nearly vertical, 20-foot wave front hit the bridge. The town clock of Waiakea stopped at that minute and still stands as a monument. The waves went on for hours.

Head for high ground and stay there

In Onagawa, Japan, waves up to 14 feet, some carrying floating timber like battering rams, kept coming for several hours. Elsewhere in Japan the tsunami killed 138 people; in Onagawa no one died, probably because so many went to high ground. A fireman on early watch at the harbour, Kimura Kunio, noticed the water moving strangely and raised the alarm. Nearly three hours after the first large wave, crowds were still on the hillside when another arrived.

Japan's written records show the same lesson centuries earlier: in 1700, people in Miyako fled to high ground from the Cascadia tsunami, which there destroyed 13 houses and set off a fire that burned 20 more.

Abandon your belongings

Ramón Atala was Maullín's most prosperous merchant. Between the first and second waves he went into his waterfront warehouse, some say to rescue money; by one account his wife grabbed his hair to hold him back. The second wave washed the building away, and his body was never found.

Don't count on the roads

Minutes after the quake, René Maldonado's horse had to leap new cracks in the road out of Maullín; the waves soon cut the road with channels too wide for any horse. Near Valdivia, landslides blocked roads and even dammed a river, whose later bursting flooded parts of the city. The family of José Navarro, on a low peninsula, stayed home until they saw a low wall of water less than a mile away. They had half a mile to go to reach the bridge to high ground, and watched the first wave destroy it in front of them.

Only if trapped: a sturdy building, a strong tree, something that floats

These are last resorts for people caught on low ground, and they worked only sometimes.

• A building. Cut off, the Navarros made for Ramón Atala's barn three-quarters of a mile away. With 14 others they spent the night in its loft while the water ran beneath them. Mr. Navarro, who had gone back for a few things, reached it just as the second wave did.
• A tree. At least a dozen people near Maullín survived in trees. Ramón Ramírez, 15, rode out the waves in a cypress while the water swirled around its base; a pregnant María Vera and eight others clung to a peta tree all night. Others died when the trees they climbed were toppled.
• Something that floats. Swept off her feet by the second wave, Nelly Gallardo found herself clinging to a wooden hitching rail; at dusk the current carried it into a tree, whose branches held her and two others through the night. Armanda Cubate, her 4-year-old nephew and five others rode the roof of her family's house when the third wave carried it away. Her parents drowned.

What the waves leave behind

A tsunami leaves sand, the wreckage of houses, and bodies. In Quenuir, 105 people died, a quarter of the village, most of them caught in boats they had taken to just after the quake; the waves even washed away the village cemetery, and crosses and a coffin turned up more than 3 miles upriver. Near Queule, houses floated off "like ships" with their stoves still smoking. The tsunami left a layer of sand several inches thick on fields, and a similar layer from 1700 still covers a Native American fishing camp on Oregon's Salmon River.

Expect the land to sink

The earthquake itself dropped coastal land by as much as 8 feet along the thinned edge of the plate, letting the tides flood pastures, farms and forests; Ramón Atala's pine plantation became a salt marsh. Cascadia's coast sank the same way in 1700.

Expect company

Yolanda Montealegre's large house outside Maullín, on slightly higher ground, came through dry. In the weeks after the disaster she sheltered 40 families there.

The lessons

1. The earthquake may not kill you; the tsunami may.
2. Treat strong shaking, or the sea drawing back or rising fast, as a warning.
3. Heed official warnings, even ambiguous ones.
4. Expect many waves, for hours; the first is rarely the largest.
5. Go to high ground, or at least inland, and stay there until the tsunami is really over.
6. Leave your belongings.
7. Expect roads to be broken or blocked.
8. Only if trapped: an upper floor or roof of a sturdy building, a strong tree, anything that floats.

Sources

• U.S. Geological Survey, Circular 1187, "Surviving a Tsunami: Lessons from Chile, Hawaii, and Japan," compiled by Brian F. Atwater, Marco Cisternas V., Joanne Bourgeois, Walter C. Dudley, James W. Hendley II and Peter H. Stauffer (1999, revised 2005), with the Pacific Tsunami Museum, Universidad Austral de Chile, the University of Tokyo and others. The booklet's photographs, many lent by others, are not reproduced.