Last year, the Eastern coast of Japan was struck by a massive 9.0 earthquake and tsunami. Since that happened, you've heard researchers talk about how it was not the first time that region had experienced an earthquake that large. Although the 2011 Tohoku earthquake has been called the biggest earthquake in Japan's recorded history, that's really only describing the relatively short history of scientifically measured earthquakes. The Japanese have kept written records, describing earthquakes that sound as though they could have been every bit as destructive. And those records date back 1600 years.
But written records aren't the only way of preserving local memories, or warning future generations about the destructive power of the Earth.
Geologic evidence shows that North America's Pacific Coast has experienced earthquakes on the scale of the Tohoku earthquake. (In fact, the Pacific Northwest is probably due for one of these large quakes. It's not an "if", but a "when".) The last time it happened, nobody in the area was keeping written documents. Instead, the story of a massive earthquake and a devastating tsunami—which probably occurred around the year 1700—have become a part of oral storytelling traditions. Ruth Ludwin, a seismologist at the University of Washington, has been collecting these stories since the early 1990s.
"There was a shaking, jumping up and trembling of the earth beneath, and a rolling up of the great waters."
So says an ancient tale told to generations of Quilleute and Hoh Indians. Variations of this saga of an epic battle between the Thunderbird and the Whale are found among Pacific Northwest Tribes from Vancouver Island to Oregon's Tillamook tribe.
The Whale was a monster, killing other whales and depriving the people of meat and oil. The Thunderbird, a benevolent supernatural being, saw from its home high in the mountains that the people were starving. The great bird soared out over the coastal waters, then plunged into the ocean and seized the Whale.
A struggle ensued first in the water, the tribal tale says. "The waters receded and rose again. Many canoes came down in trees and were destroyed and numerous lives were lost."
The Thunderbird eventually succeeds in lifting the evil Whale out of the ocean, carrying it "high into the air (and then) dropping it to the land surface at Beaver prairie. Then at this place there was another great battle."
"A picture began to emerge that looked a lot like what you'd expect from a major quake," she said. One tribe even had what sounds like an explanation for aftershocks, noting Whale had a son, Subbus, who took Thunderbird several more days to locate and kill. The earth-rumbling struggle persisted, but eventually Subbus was subdued.
"I can't say for certain this was the 1700 event, but it sure sounds like it," Ludwin said. "You hear the same story from tribes all along the coast."
Image: Simulation from a U.S. Geological Survey research report, showing how the 1700 Cascadia earthquake might have created a tsunami that reached Japan. Written documents in Japan describe a tsunami from that year with no "parent" earthquake. Cascadia might be the source of the so-called "orphan" tsunami. You can read the full paper online.