This week - 326 years ago - a massive earthquake shook the Pacific Northwest. Back then, there was no such thing as a seismometer. Here’s how scientists uncovered the date of the 1700 Cascadia quake ... and why preparedness matters today more than ever! For more about earthquakes, visit earthquake.ca.gov. And for more about tsunamis, visit tsunami.ca.gov. | California Governor's Office of Emergency Services

Cascadia Megathrust: How We Know When It Happened For centuries, the Cascadia Megathrust earthquake was a puzzle. The Pacific Northwest landscape showed clear signs of a massive earthquake and tsunami, but no local written records explained when it occurred. One key clue came from across the Pacific. In January 1700, Japanese records described a tsunami that arrived without a nearby earthquake. By tracing how tsunami waves travel, scientists linked it to a powerful quake off North America’s coas

The 1700 Cascadia earthquake occurred along the Cascadia subduction zone on January 26, 1700, with an estimated moment magnitude of 8.7–9.2. The megathrust earthquake involved the Juan de Fuca plate from mid-Vancouver Island, south along the Pacific Northwest coast as far as northern California. The plate slipped an average of 20 meters (66 ft) along a fault rupture about 1,000 kilometers (600 mi) long. Westen Travels - November 2022, Siletz Bay Oregon | Vincent Easley II