The Pacific Northwest is a region defined by its geology as much as its rugged coastline, drippy westside forests, fertile farms, and canyoned eastside grasslands. These landscapes have been forged by volcanoes, crumpled by faults and sculpted by water and ice. But the Northwest's geologic DNA is rooted in volcanic activity. From the ancient lavas of Washington's Selkirks that freed the planet from a global ice age, to the world-class flood-basalts...