Saturday is the 319th anniversary of the Jan. 26, 1700 megathrust 9-plus earthquake on the Cascadia Subduction Zone that devastated the coasts of Northern California, Oregon and Washington. The subduction zone ruptured along its full length of over 600 miles, and the shaking lasted for several minutes, causing coastal land to suddenly drop and become flooded with seawater.
The Native Americans who lived through the catastrophic event preserved the memory — and tried to explain what happened — by creating a colorful oral history.
In Washington, the Quileute and the Hoh describe a horrific battle between Thunderbird and Whale; the mountains shook, and the ocean rose and covered the land. On Vancouver Island, British Columbia, the Nuu-chah-nulth people tell of a dancer who accidentally kicked a drum and got “earthquake-foot,” so every step caused an earthquake.
Nine or 10 hours after the shaking stopped on the West Coast, a tidal wave hit Japan, and observers there were puzzled by the “orphan tsunami.” The wave didn’t seem to have any local cause, and no one could figure out where it came from. Nonetheless, the time, date and details were fastidiously recorded in several municipalities. It took 300 years for scientists and historians in the U.S. and Japan to connect the 1700 orphan tsunami with the catastrophic event on the Cascadia Subduction Zone.
Remnants of the disaster are still visible on the North Coast to this day. One example is the Neskowin Ghost Forest. The trees, 150 to 200 feet tall, disappeared when the land suddenly dropped, and they were covered with debris. Stumps, more than 2,000 years old, according to carbon dating, appeared occasionally on the beach over the years, then re-emerged for good during the winter of 1997-1998.
So when will the next Cascadia “big one” hit? The Oregon Office of Emergency Management estimates there is a 40 percent chance that a megathrust earthquake of 9.0-plus magnitude will occur in the next 50 years. Are you ready?