A series of newly discovered faults on the north and south flanks of Mount Hood are capable of producing a massive earthquake, researchers said Monday, noting that large swaths of the region could be at risk.

The discovery, made by Ian Madin of the Oregon Department of Geology and Mineral Industries and Ashley Streig, assistant professor of geology at Portland State University, poses yet another risk to the region, coupled with the Cascadia Subduction Zone off the Oregon coast and the fault system that runs under Portland's west hills.

The Mount Hood faults are capable of producing a 7.2 magnitude quake, researchers said in a news release, larger than the Loma Prieta earthquake that struck San Francisco in 1989, causing dozens of fatalities and widespread destruction.

The Mount Hood faults are closer to Portland than the epicenter of the Loma Prieta quake was to San Francisco so the damage could be worse, Streig said.

The faults on the mountain differ from those off the coast, though.

"This would be a crustal earthquake as opposed to the Cascadia subduction zone earthquake Portland has been bracing for," Streig said. "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."

The faults north of Mount Hood run all the way to the banks of the Columbia River and, were they to rupture, rail lines in the Gorge could be disrupted and power generation at Bonneville Dam could be put in jeopardy.

The communities of Hood River, White Salmon, Stevenson, Cascade Locks, Government Camp and the Villages at Mount Hood could all see damage from a quake on the newly discovered faults. In Portland, researchers said a quake would cause strong ground motion and areas near water could see liquefaction of ground soil.

-- Kale Williams

kwilliams@oregonian.com

503-294-4048