Geologic Information about Washington: From the USGS, an overview of this region's geology.
Pacific Northwest Seismograph Network: Operates seismograph stations, locates earthquakes in Washington, and disseminates information on regional earthquake and geologic hazard activity.
The Mima Prairie Mounds Just South of Olympia, WA: Photos of naturally occurring earth mounds that are located in Capitol State Forest by Andy Ganse.
The Pacific Northwest Seismograph Network: Based at the University of Washington, the PNSN operates seismograph stations and locates earthquakes in Washington and Oregon and provides information on Pacific Northwest earthquake activity and hazards.
Washington Division of Geology and Earth Resources: Part of the Department of Natural Resources. Includes bibliography of Washington geology, news, FAQ, links, and educational resources.
Washington Obsidian Sources: List of locations that are sources of obsidian across the state. Also includes a scientific bibliography.
Washington State Rockhounding: Trips and photos, classifieds, site map, weather forecast, government contacts, and further reading.