Following the Clues to Find A Killing Fault

Cascadia’s Fault: The Coming Earthquake and Tsunami That Could Devastate North America

by Jerry Thompson

Counterpoint Press


Like the rocks and faults it explains, the theory of plate tectonics, newly formed at the time of Alaska’s 1964 earthquake, moved slowly, incrementally, into widely accepted thought. Even 20 years later, the scientific community was slow to agree that slabs of the earth’s crust floated on semi-liquid rocks, crashing into each other with regular frequency, was a viable concept. It took the Mexico City earthquake in 1985, a magnitude 8 shaker that killed as many as 40,000 people and destroyed or damaged almost 6,000 structures, for the theory to take hold.

Even then, as Jerry Thompson so vividly details in his book, Cascadia’s Fault: The Coming Earthquake and Tsunami That Could Devastate North America, acceptance was only the beginning. Scientists were just realizing all earthquakes were not created equal, nor were they caused by the same mechanics. In fact, just recognizing the mechanics, intervals, cause, effects, and everything else about earthquake, large and small, was showing itself to be a monumental task.

In part history, mystery, scientific searching, and quest, Cascadia’s Fault is a look at the many aspects of seismology, geology, earthquakes, and tsunamis, and the way humans tend to ignore dangers even when they’re right in front of them. Focusing specifically on the Cascadia Subduction Zone off the State of Washington, Thompson explores the subject in great depth, with astonishing technical detail that doesn’t make a non-scientist’s eyes glaze over. It’s a fascinating read.

Cascadia, Thompson writes, is “virtually identical to the offshore fault that devastated Sumatra – almost the same length, the same width, and with the same tectonic forces at work. This fault can and will generate the same kind of earthquake … magnitude 9 or higher. It will send crippling shockwaves across a far wider area …”

Hyperbole it’s not, as he follows through with very plausible details and scenarios. He also warns a Cascadia rupture will trigger other, more well-known faults – think San Andreas, Denali, etc. – causing undersea landslides, more earthquakes – kind of like dominoes falling one after the other. And instead of occurring every 500 to 550 years, as once thought, scientists now think these huge, earth-shattering events happen every 300 years or so. Cascadia last moved about 310 years ago.

The book, after an excellent Introduction by Simon Winchester, begins with Thompson and his wife at a bar in San Francisco on Christmas Eve, 2004. As every eye in the bar turned to the television, “Jimmy Stewart’s smiling face [was] wiped off the screen by a mountain of angry seawater.” The Sumatra earthquake had just unleashed a tsunami onto the region with devastating force. Thompson vividly recalls the details:

“The first horrifying, mesmerizing wave crashed against a seawall, jetting skyward in salty white torrents, tearing through a fringe of palm trees like a monsoon river, across a hotel pool deck and a manicured square of green lawn. The darkening surge roared uphill through narrow, cluttered streets choked with tourist luggage, broken timbers, small motorcycles with their riders struggling to stay vertical, cargo vans overturned and bulldozed by white froth into market stalls.”

But what does a tsunami in the Indian Ocean have to do with me, you ask. It’s a rare event, the first time something like that has ever happened. No real risk to most of us, right?

Wrong. Thompson is adamant about the wrongness. Things like this have happened before, all over the world, some even bigger and more devastating than Sumatra. We just don’t have any written records. That’s the key, he says. Humans always think in terms of human time – recorded history doesn’t mention any such disasters, so they didn’t happen. But geologic time scoffs at our puny minute-outlook. Thompson explains our recorded and social history don’t go far enough back to tell us the story.

But geologic history is written in stone – literally. And this is where the book takes a turn into mystery, although instead of a “who-dunnit,” it’s a “what-dunnit.” Thompson details the search for evidence that Cascadia has ripped the world apart in the past, a likely indicator it will again. Climbing mountains, digging into deep trenches, searching under the sea, and mucking about in old marshes, Thompson and his scientist heroes dig for the truth, looking for ancient evidence of mega-quakes and earth-scouring tsunamis in

And, as they get deeper into the search, they discover there are actually written human records of these mega-events. They just weren’t recorded as earthquakes. Legends, oral histories — even Japanese bureaucratic records – tell of devastating waves, shaking, landslides, and other earthquake-related disasters, indicating there are more of these massive events than we thought.

And though this is a hard science tome, with technical details and scientific theories and discussions, it is far from a dry, dull read. It pulls one in, not the least because of Thompson’s writing. A documentary maker by trade, he has a way with words that, while portraying massive destruction and despair, is still lyrical and laden with imagery:

“For half a minute that must have felt like a life time, 320,000 square miles … of Central and North America shuddered and rumbled up and down and from side to side. More than 20 million people … felt the earthquake. … Like the lowest bass notes of an upright bass, this fractured slab of sea floor played fatal music, a throbbing rhythm that pulsed with stunning efficiency through 190 miles of continental crust to reach the capital city. The first burst of notes lasted roughly thirty seconds …”

For anyone interested in geology, seismology, scientific discovery, history, or just a well-written book that will leave you thinking – hard – Cascadia’s Fault is one that should be on your “To Read” list.