Oregon Public Broadcasting

Oregon’s wet, hilly terrain has long been thought to be landslide territory. But the first in a new series of maps that government geologists released this week show more slides than many experts expected.

James Roddey is a spokesman for the state Department of Geology and Mineral Industries -- the agency responsible for the new maps. He says the new laser technology  has identified lots of historic landslides -- in places like the Linnton neighborhood on the western edge of Portland.

James Roddey:  “For example, the Linnton quadrangle that we just released has 600 identified landslides on it - these are existing landslides. Knowing where existing landslides have happened, it can tell people, well, there’s a possibility that a landslide may happen in that area, as well.”

Roddey says it is also possible that slide areas can be stable  for decades, or longer.

The two new Portland area maps are the first step in an effort by state geologists to chart most of the populated places in Oregon. Those include the Willamette Valley, central Oregon, the Columbia Gorge, and the Coast.