The Pacific Northwest volcanoes continue to be a geologically active area . The most geologically recent volcanic eruptions include : The Pacific Northwest is seismically active . The Juan de Fuca Plate is capable of producing megathrust earthquakes of moment magnitude 9 : the last such earthquake was the 1700 Cascadia earthquake , which produced a tsunami in Japan , and may have temporarily blocked the Columbia River with the Bonneville Slide . More recently , in 2001 , the Nisqually earthquake ( magnitude 6.8 ) struck northeast of Olympia , Washington , causing some structural damage and panic
1700 Cascadia earthquake
1700 Cascadia earthquake
Geology of the Pacific Northwest