A magnitude 6.0 earthquake struck in the Pacific Ocean about 180 miles off the coast of Oregon late Thursday night, sending tremors across the US West Coast. Residents in cities including Portland, Eugene, Salem, and Coos Bay reported light shaking, even though the epicenter was far offshore. A smaller magnitude 3.1 aftershock followed early Friday morning, and the US Geological Survey announced a 65 percent chance of additional aftershocks over the weekend. The quake occurred along the Juan de Fuca Plate, part of the Cascadia Subduction Zone — a massive fault line stretching nearly 700 miles along the coasts of Canada and the United States. While the region’s tsunami warning system was briefly activated, officials confirmed no dangerous waves formed and no injuries or property damage were reported.

Scientists have long warned that the Cascadia Subduction Zone is capable of producing a catastrophic earthquake, often calling it a “Sleeping Giant.” Though the likelihood of a major rupture above magnitude 7.0 in the immediate future remains low, recent studies suggest a powerful quake is almost inevitable by the year 2100, with a 37 percent chance of occurring within the next 50 years. Experts estimate that a magnitude 8.0 to 9.0 earthquake could trigger a massive tsunami with waves up to 100 feet high, devastating coastal communities. Emergency agencies warn such an event could injure hundreds of thousands and destroy hundreds of thousands of buildings. The last major Cascadia earthquake occurred in 1700, producing a deadly tsunami that wiped out entire villages — a haunting reminder of the region’s seismic potential.