You look at the land prices in Seattle and Rio de Janeiro. In Rio, the poor people live in the high hazard zones. In Seattle, the rich people do. Seattle and the Puget Sound region have classic layer-cake geology, with glacial deposits prone to sliding. A similar layered geology of ancient river deposits makes slopes unstable as far south as Oregon City.
Roadways are hard hit, as well.
Many of the roads were built 60 to 80 years ago, and heavy rainfall has caused them to fail. Development itself, with its impermeable sidewalks and driveways, has exacerbated slide problems by concentrating runoff, rather than allowing it to soak into the ground, Pratt said. Burns, professor of geology at PSU, said Carlyon Beach, and damage to 17 homes at nearby Sunrise Beach and Sunset Drive, has been a wake-up call to Thurston County. He said many counties, particularly rural ones prime for development, are ill-equipped to deal with the demands of growth. They don't know, but everybody expects them to be perfect and carry all the liability.