5.4.6: Native Americans Were Making Observations, After All
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Could there be confirmation in the oral traditions of Native Americans living along the coast at that time? Garry Rogers of the Pacific Geoscience Centre in Sidney, B.C., found in the provincial archives at Victoria a tradition that an earthquake had struck Pachena Bay on the west side of Vancouver Island during a winter night. It was discovered the following morning that the village at the head of the bay had disappeared. This is consistent with Satake’s calculated time of the earthquake based on the Japanese tsunami. Traditions of the Chinook included references to ground shaking. The Makah, Tillamook, and Coos tribes have stories of the inundation of coastal settlements by “tidal waves” or tsunamis.
Gary Carver’s wife, Deborah Carver, has collected stories recorded in the early part of the twentieth century from Wiyot, Yurok, Tolowa, and Chetco bands living on the coast of northern California and southern Oregon (see Yurok oral history at the beginning of this chapter). Many of these stories tell of strong shaking from a great earthquake along at least two hundred miles of coastline, followed by many aftershocks, liquefaction of sediments, subsidence of coastal regions, and tsunamis that lasted for several hours. Six of these stories indicated that the earthquake struck at night. The earthquake and tsunami destroyed many villages and drowned many people living there. Carver reported that one purpose of the Yurok “Jumping Dance” was to repair or re-level the Earth after an earthquake.
The story that follows is from an interview recorded by A. L. Kroeber in his book Yurok Myths:
"And from there [Earthquake and Thunder] went south—They went south first and sank the ground—Every little while there would be an earthquake, then another earthquake, and another earthquake—And then the water would fill those [depressed] places—”That is what human beings will thrive on,” said Earthquake. “For they would have no subsistence if there were nothing for the creatures [of the sea] to live in. For that is where they will obtain what they will subsist on when this prairie has become water, this stretch that was prairie: there will be ocean there.”—”Yes, that is true. That is true. That is how they will subsist,” said Thunder. “Now go north.” Then they went north together and did the same: they kept sinking the ground. The earth would quake and quake and quake again. And the water was flowing all over."
This story spoke of a land that sank into the ocean during an earthquake—exactly what Brian Atwater, Alan Nelson, and Deborah’s husband, Gary, had concluded from their study of marsh deposits on the Pacific coast. In addition, Gary Carver studied a subsidence site in northern California and concluded that the subsidence occurred after the leaves had fallen and before new growth appeared on the trees; that is, probably during the winter.
Rick Minor suggested that Cascadia Subduction Zone earthquakes might explain an oddity of Native American archaeology along the coast. Sea level rose rapidly from twelve thousand to five thousand years ago, as glacial ice sheets melted, and then stabilized close to the present level four to five thousand years ago. But there is very little archaeological evidence for Native American settlement along the coast prior to about two thousand years ago. Could the lag in settlement be a result of abrupt coastal subsidence and great tsunamis accompanying past subduction-zone earthquakes? Were Native Americans more concerned about earthquake and tsunami hazards than we are today? Minor described one Native American site that is overlain by sand deposited by a tsunami (Figure 4-20).