Newly found Mount Hood faults could trigger 7.2 quake

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.

KGW reported Monday the fault networks are located to the north, south and southwest of Mount Hood and extend to the Columbia River.

The fault lines 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.

The two researchers discovered the faults during analysis of new high-tech imaging, then verified the finding through field research.

A 7.2 magnitude earthquake is larger than the 1989 earthquake near the San Francisco Bay Area. Streig said the faults on Mount Hood are closer to Portland that the epicenter of the 1989 earthquake was to San Francisco.

Streig said it would be a “crustal earthquake,” unlike the offshore Cascadia subduction zone quake much of the state has been bracing for. Subduction zone quakes are deeper and last longer but are lower in amplitude, he said, while one near Mt. Hood would be shorter but “strong enough to knock you off your feet.”

He said the Portland area would have “strong ground motions and could suffer liquefaction damage along waterfront areas.”