The Orphan Tsunami and the Ghost Forest

Whale was a destroyer. Whale attacked and killed all the smaller whales, which provided food and oil to humans. The people began to starve.

From her home in the mountains, Thunderbird spied the distress of the humans on the coast. She soared over the ocean, waiting for Whale to surface. When Whale arrived for air, Thunderbird dived, plunging her talons into the mammoth destroyer. She lifted Whale out of the water, causing enormous roiling of the ocean.

Thunderbird flew Whale over the land. Tiring under the immense weight, Thunderbird dropped Whale onto the ground. The land shook with tremendous fury. Whale and Thunderbird entered into a cataclysmic battle. Whale fought for his life with the energy of the elements. Each time Thunderbird grasped Whale and dropped him to the ground, the earth itself shuddered. Eventually, Thunderbird lifted Whale to her nest in the mountains, where the final titanic battle transpired. Thunderbird ripped Whale into pieces and tossed him around, where the slivers turned to stone.

Where Whale and Thunderbird battled, trees were uprooted and they never grew back. Many settlements were completely destroyed. 

Late 19th-century depiction of Thunderbird and Whale from Vancouver Island

From the Hoh tribe, this rendition is one of many from the Indigenous peoples of the Pacific Northwest that entered the white historical register, starting in 1805, as the Lewis and Clark expedition reached the ocean. Natives did not have a written history, but the oral tradition carried tales across the ages. Though the combatants here are mythical, the references to trouble in the ocean, quaking earth, and the inexplicable loss of trees echo across the stories from tribe to tribe, pointing toward potential real connections in the natural world.

To Lewis and Clark and to the other white settlers, these notions of tectonic unrest seemed alien. Unlike San Francisco or Los Angeles, Seattle and Portland do not carry the connotation of seismic hotbeds. In the history of the United States as a nation, no major earthquake has hit the Pacific Northwest. Alaska, yes; California, yes (though not as major as we usually envision); Washington and Oregon, not really.

On the other side of the Pacific, Japan starkly differs from the story of the northwestern United States in two ways. The island nation is well known for its earthquakes. Minor temblors are a way of life. Major quakes are a constant threat. Further, unlike the native populations in the northwest, the Japanese have an extensive written record. They are particularly adept at preserving one of the most devastating side effects of earthquakes: tsunamis.

Tsunamis have ravaged Japan through time immemorial. The Japanese have long understood that the terror from the ocean often stems from an earthquake. The video above features footage of the famous 2011 tsunami that followed a monster earthquake, inundating the coast and even threatening a nuclear reactor with a major disaster.

The historical record phenomenally archives the tsunamis of the past. One particular instance, however, stands out from the hundreds of years of documentation: the orphan tsunami. This specific watery apocalypse occurred in 1700 and raked over 600 miles of the Japanese coast. It was odd because no earthquake preceded the tsunami. In other words, it had no parent.

For centuries, the cause of the orphan tsunami baffled historians and scientists. When geology and seismology advanced in sophistication, scientists went on the hunt to discover the root of the orphan tsunami. They searched for forensic geology all around the Ring of Fire, the famous zone of volcanic and tectonic unrest that circles Asia, North America, and South America. They found nothing from any of the usual suspects (Chile, Alaska, California).

In 1996, a now-famous paper in the journal Nature went Sherlock Holmes on the world of geology. In The Sign of the Four, the detective uttered, “How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?” As strange as it might seem, the authors stated the orphan tsunami must have been the result of a gargantuan earthquake in the Pacific Northwest.

The Cascadia Subduction Zone - USGS

The San Andreas Fault gets all the plaudits, but lurking farther north is a fault system we didn’t know existed until the 20th century. And this system – the Cascadia Subduction Zone – is a monster that makes the San Andreas Fault look like a bothersome gnat.

Part of the reason for the difference in danger lies in the type of fault. The San Andreas is a strike-slip fault, meaning it moves side-by-side. These systems can create large quakes, but they do not traditionally produce truly catastrophic examples. The Cascadia system is, as the name implies, a subduction zone. This means that the plates that form the fault are smashing into one another. Instead of moving along the edges, when two plates collide one of them is pushed deep into the earth’s upper regions. One of the plates essentially gets munched by the crash. The result, as you might expect, is often unimaginably horrific.

Geologists realized the Pacific Northwest is sitting on top of a time bomb and the clock is ticking. Despite the lack of written history, megaquakes must have occurred numerous times in the past. Were all the Indigenous tales about earthquakes and tsunamis anchored in reality? Had the orphan tsunami of 1700 been caused by the Cascadia Subduction Zone? In 1996, Scientists believed the answer was yes and just a year later they received confirmation thanks to an unlikely source: trees.

The Copalis Ghost Forest - photo by USGS

The Indigenous stories adamantly refer to areas where Whale and Thunderbird uprooted the trees, damaging the earth so badly that they never reappeared. In some spots on the Pacific coast, areas of widespread arboreal destruction are rampant. In a few cases, the trees were destroyed, but their husks still stand in what we call ghost forests.

These trees died thanks to saltwater. The popular notion is they died slowly, as the water levels rose, poisoning the trees with salt little by little. But in the late 1980s, in a ghost forest at the mouth of the Copalis River, scientists discovered that theory was wrong. Sediments in the soil pointed to rapid subsidence. Put simply, the trees died suddenly when the elevation of the coast dropped instantaneously. These sudden drops happen because of giant tectonic events.

The cedars in the Copalis Ghost Forest had another surprise in store. Their corpses are old. A dendrochronological analysis in 1997 showed the trees all perished simultaneously. They also discovered the growth rings stopped in a discernible year. That year was 1699!

Since trees don’t grow in the winter, the summer of 1699 was the last year these trees lived. Sometime between August 1699 and May 1700 the trees died. Suddenly, the connection between the orphan tsunami and an earthquake in the Cascadia Subduction Zone was solidified!

Further, since 1700 is not a point in the undiscernible past, researchers undertook an analysis of the Indigenous tales about Whale and Thunderbird. In many cases, the families could trace the generations to the dawn of the 18th century. The average year the backward analysis reached? 1701!

The good news is the mystery finally seemed to be solved. Science and folklore had both pointed toward a definitive event in the Cascadia Subduction Zone in 1700. The bad news is scientists now knew the Cascadia Subduction Zone is capable of producing civilization-altering tragedies.

Seismic activity from a potential 9.0 magnitude earthquake in the Cascadia Subduction Zone - USGS

We now know that, though the Cascadia Subduction Zone does not produce many noticeable, small tremors, the area experiences a massive earthquake, on average, every 243 years. In the past 10,000 years, the area produced 41 earthquakes.

Again, this information possesses both good and bad news. The good news is the quakes don’t happen often. But do the math. At an average of 243 years, the zone is now well past the typical period for the next event. 1700 + 243 = 1943. Further, this large period couldn’t have happened at a worse time for humanity in the region. The last catastrophic temblor occurred before seven million people resided there. We had no idea the entire region sprouted up on one of the world’s biggest powder kegs. FEMA predicts many tens of thousands of people will die when the next tsunami arrives in the region.

I first encountered this fascinating intersection of science and history in one of the best articles on nature I’ve ever consumed. In “The Really Big One,” Pullitzer winner Kathryn Schulz lays out why Seattle, Portland, and numerous other pockets of humans are in serious trouble when, not if, the Cascadia Subduction Zone next rises from the ashes. This piece ties together so many wonderful insights and interesting scientific history; please take the time to read it (see the Further Reading and Exploration section below).

Few nature stories weave puzzles, myth, history, and science as this one does. It’s a beautiful amalgamation, but a sobering one. One day, thousands of people will die, an entire coast will be reshaped, and lives will be forever altered. Yet this future reality is just nature marching forward. Hopefully, we can learn the needed lessons and protect as much life as possible.

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