The State of Oregon Office of Emergency Management has released a new ‘Cascadia Playbook’ helping outline the first two weeks of government response in the face of a 9.0 Cascadia Megaquake. The playbook provides a two-week blueprint for the state’s response and expectations for prioritizing Oregon's recovery from what would be the deadliest natural disaster in the U.S.
Other than just earthquakes, a 9.0 magnitude earthquake could trigger volcanic eruption, or tsunami that would hit the 700-mile Cascadia Subduction Zone, rippling from the coastal counties and impacting much of the state and neighboring Washington. Emergency planners estimate coastal areas would have as little as 15 minutes notice to escape an incoming tsunami, and as many as 25,000 people could die. About a million Oregonians could be impacted in other ways: needing shelter, food and medication while waiting for help.
The Cascadia subduction zone (also referred to as the Cascadia fault) is a convergent plate boundary that stretches from northern Vancouver Island in Canada to Northern California and is responsible for deep earthquakes and the active volcanism of the Cascade mountians. It has the potential for very large earthquakes above a 9.0 magnitude that could impact the largest population centers in the region, such as Vancouver, Victoria, Seattle and Portland and has included such notable eruptions as Mount Mazama (Crater Lake) about 7,500 years ago, the Mount Meager massif (Bridge River Vent) about 2,350 years ago, and Mount St. Helens in 1980.
The last Cascadia Megaquake occurred January 26, 1700 with an estimated moment magnitude of 8.7–9.2 and stretched from mid-Vancouver Island, south along the Pacific Northwest coast as far as northern California stretching for more than 1,000 kilometers (620 miles), with an average slip of 20 meters (66 ft), and resulted in a massive tsunamai felt as far away as Japan. Cascadia Megaquakes occur every 300-500 years.
As wildfires grow stronger each year, and drought and flooding continue to impact the different regions of Cascadia, disaster planning, and regional growth planning has been shown to be one of the largest areas for cooperation between Washington, Oregon and British Columbia.
To be ready and prepared, it is recommended that every family be ready with at least two weeks of food and water.