CASCADIA: The Megaquake That Could Break America’s West Coast | The Overdue Files

"Our operating assumption is that everything west of Interstate 5 will be toast." That's what FEMA's own regional director said about a single fault line most Americans have never heard of — the Cascadia Subduction Zone. For most of the 20th century, scientists assumed the Pacific Northwest coast was seismically quiet. There was no written record of a great earthquake here. Then a geologist walking a tidal flat in 1986 found something that shouldn't exist — and pulled a 300-year-old catastrophe back into the light. In this video, we reconstruct the 1700 Cascadia earthquake and tsunami using four independent lines of evidence: 🪵 Ghost forests and buried soil layers on the Washington coast 📜 Japanese village records describing an "orphan tsunami" 🌊 10,000 years of submarine landslide deposits pulled from the seafloor 🗣️ Oral histories carried for ten generations by Pacific Northwest coastal nations Together, they don't just prove the quake happened — they pinpoint the exact night: January 26, 1700, around 9:00 PM local time. And the same fault that broke then is still locked today, still storing energy, still overdue. This is the story of how a disaster with no written history was reconstructed from wood, paper, mud, and memory — and what it means for the roughly 8 million people living on top of it now. 🔔 Subscribe to The Overdue Files for more deep dives into the disasters history almost forgot. ──────────── ⏱️ TIMESTAMPS 0:00 – "Everything west of I-5 will be toast" 0:40 – What is the Cascadia Subduction Zone? 1:45 – Why scientists thought the fault was safe 3:00 – The 1986 tidal flat discovery that changed everything 4:15 – The ghost forests of the Pacific Northwest 5:15 – Dating the disaster with tree rings 6:15 – Japan's "orphan tsunami" 7:30 – 10,000 years of evidence from the seafloor 8:45 – The oral histories that had the answer all along 9:45 – What happens when Cascadia breaks again 10:45 – The only question left 📚 KEY RESEARCH REFERENCED Brian Atwater (USGS) – tidal marsh & tsunami sand deposits David Yamaguchi – dendrochronology of the "ghost forest" cedars Kenji Satake – Japanese tsunami records & the "orphan tsunami" Chris Goldfinger (Oregon State University) – submarine turbidite cores Oral histories of the Huu-ay-aht, Makah, Hoh, Quileute, Yurok, and Duwamish peoples ──────────── #TheOverdueFiles #Cascadia #Megaquake #Earthquake #PacificNorthwest #TheBigOne