United States, California

California is the third largest U.S. state in terms of area. In 2005, California's estimated population was 36,132,147, making it the most populous state in the country. Approximately 68 percent of Californians live in the greater Los Angeles and San Francisco Bay Areas.

The discovery of gold in 1848 led to the California Gold Rush, which marked the opening of the Sierra Nevada region to European-American occupation and development. What began as amateur mining with simple technologies in the early years transformed by the 1860s into large-scale mining, [Page 1821]including the excavation of mines with hydrologic operations. A federal injunction put an end to immense on-site and downstream environmental impacts of hydrologic mining during the 1890s. Mining in California, however, did not stop with the end of the Gold Rush. In 2004 California ranked first in the nation in nonfuel mineral production, accounting for nearly 8 percent of the national total.

California's diverse physical landscape is now managed through a mosaic of private, federal, and state landholdings. In 1890 Sequoia National Park became California's first national park. In 1902 Big Basin State Park became the first state park in California. Today, 47 percent of the land ownership in California is under the control of the federal government (20 percent Forest Service, 15 percent Bureau of Land Management, 8 percent National Park Service, and 4 percent military), while 5 percent of California's land ownership is under the jurisdiction of the state. The other 48 percent falls under private ownership.

Located at the interface of the Pacific and North American tectonic plates, California experiences frequent seismic activity. The San Andreas Fault runs the length of California and is one of the state's most active fault lines. One of the most destructive earthquakes along the fault was the 1906 San Francisco Earthquake. In 1989 the Loma Prieta Earthquake struck along the San Andreas Fault, causing widespread damage to the San Francisco Bay Area.

There are many other active fault lines in California. The 1994 Northridge Earthquake in Southern California, which is considered by many to be the most costly earthquake in U.S. history, occurred along the Santa Monica Mountains Thrust Fault. In reaction to California's vulnerable position, the California Legislature passed a landmark law in 1972 requiring the identification of seismic hazard zones. In these zones, special geologic studies are mandatory before structures can be assembled for human occupancy.