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Back to Cascade Head and the Salmon River

It’s the year 1700. The Oregon Coast is a lush wilderness, virtually unaltered by human hands. Although large wooden sailing ships occasionally cruise by, the interior of the state – and most of the North American continent in general – is largely unexplored by Europeans. But that doesn’t mean there aren’t people and civilization here. A thriving population of Native Americans exists all along the coast, building villages among the trees, fishing for salmon in the numerous rivers, and hunting whales offshore.

But on the afternoon of January 26, the lives of these tribal people changes dramatically. The very ground under their feet begins to lurch, throwing them to the ground. The vibrations are so strong that most of these early Oregonians cannot stand for several minutes. Then, just as quickly as it began, the rumbling stops. The forest takes on an eerie silence, as though the world itself is holding its breath, waiting to see what happens next.

Offshore and unseen to the Native Americans, a large fault has burst on the ocean floor. This cataclysmic event was the result of massive geological pressures building up on the Earth’s surface. For tens of thousands of years, the North American continental plate had been grinding down on the Juan de Fuca continental plate offshore. Pressures built and built until – on January 26, 1700 – something snapped. The release of all that energy caused a tremendous earthquake, estimated to be between a magnitude 8.7 and 9.2 on the Richter Scale. In some places along the Oregon Coast, the land sunk by 20 feet (6.09 m) almost instantaneously.

But for the people of the Pacific Northwest, the earthquake was just the beginning.

Within minutes, Native Americans wandering along the coast noticed something very strange. The ocean waters were rapidly receding. This wasn’t the usually ebb and flow of the tides. This was something altogether different – the formation of a tsunami.

Probably within half an hour of the initial quake, the waters of the Pacific Ocean would’ve inundated huge sections of the coast, from California north to British Columbia. The Native Americans who lived along the banks of the Salmon River may have watched in horror as a huge wall of water came crashing through the trees and dunes, sweeping away everything in its path. Most of the Salmon River valley would’ve been submerged, and with it every plant, animal and human unlucky enough to be in the tsunami’s path.

Marked In The Mud: Clues To The Ancient Catastrophe

It’s been over three hundred years since that tragic day on the Oregon Coast, but traces of the great tsunami linger. Take a look at the photo slideshow to the right. To a trained eye, this muddy riverbank tells the story of January 26, 1700.

The stones are not native to this area and were probably used by local Native Americans to build earth ovens for cooking oysters and various kinds of meat. The red tinge to the stones is evidence that they were exposed to very high temperatures within the ovens. The ancient Roosevelt Elk bone probably also dates from this period and is a left over from a successful hunt. Both the stones and the bone were found beneath the dark mud layer obvious on the bank above. This dark band was produced when the tsunami flooded this area, the salty ocean water killed all the plant-life, and the rotting organic material stained the mud black.

Related Information: Earthquake and Tsunami