Mount Hood is a potentially active stratovolcano in the Cascade Volcanic Arc of northern Oregon. Researchers have discovered active fault lines on Mount Hood that could potentially trigger a 7.2 magnitude earthquake, devastating communities and infrastructure as far west as Portland. The fault networks are located to the north, south and southwest of Mt. Hood and extend to the Columbia River.
A 7.2 magnitude earthquake is larger than the 1989 earthquake near the San Francisco Bay Area. The faults on Mount Hood are closer to Portland that the epicenter of the 1989 earthquake was to San Francisco.
This would be a crustal earthquake as opposed to the Cascadia subduction zone earthquake Portland has been bracing for. Subduction zone quakes are deeper below the surface, they last longer — as long as seven minutes — but they are lower in amplitude. The kind of quake we would get from Mt. Hood would be shorter — 20 seconds to less than a minute — and would be strong enough to knock you off your feet.
A large quake like that would pose a significant hazard to the cities of Hood River, Odell, Parkdale, White Salmon, Stevenson, Cascade Locks, Government Camp and the Villages at Mount Hood.
The Portland metro would experience strong ground motions and could suffer liquefaction damage along waterfront areas.
The new fault lines on Mount Hood were found by Ian Madin of the Oregon Department of Geology and Mineral Industries and Ashley Streig, an assistant professor of geology at Portland State University while analysing new high-tech imaging. They then corroborated their finding through field research.