Roadside Geology of Washington

Marli B. Miller and Darrel S. Cowan Washington is alive with geologic activity: It’s home to the most active volcanoes in the lower 48, earthquakes regularly rattle the populated Puget Sound region, the potential of landslides increases with each soaking rain, and tsunami evacuation routes alert tourists in Olympic National Park to the active plate boundary just off the coast. The only geologic hazard Washingtonians need not fear, at least not with the continued trend of global warming, is another Ice Age flood. More than forty of the biggest floods known in the history of Earth scoured the Channeled Scabland of eastern Washington, the most recent only about 15,000 years ago. Since the first edition of Roadside Geology of Washington appeared on the book shelves in 1984, several generations of geologists have studied the wild assortment of rocks in the Evergreen State, from 45-million-year-old sandstone exposed in sea cliffs at Cape Flattery to 1.4-billion-year-old sandstone near Spokan