The tafoni weathering formation featured at El Corte de Madera Creek Preserve is a particularly accessible example of an uncommon phenomenon, but there are several other places to see tafoni in the Bay Area. At Castle Rock State Park west … Read more
The San Francisco Bay Area's crazy quilt-pattern of rock formations -- shaped by earthquakes -- are the key to understanding the region's landscapes. From ice-age dune sand in San Francisco to recently subsided land in the Santa Clara Valley or the veritable maze of earthquake faults in the East Bay, the geology is a fascinating blueprint of the region's natural history.
Geology of the San Francisco Bay Region, by Doris Sloan, UC Press, 2006, 360 pages, $17.95 www.ucpress.edu “The world-famous Bay Area rocks tell a geologic story that reads like a Russian novel with a very large cast of characters. Because … Read more
You can easily visit the 10-million-year-old Sibley Volcano (see Voice of the Volcano, April-June 2005) in the hills above Oakland. And college geology classes often visit the Nicasio Dam in West Marin to see pillow basalt lava that erupted deep … Read more
The open hills along the Carquinez Strait are home to working ranches and open space preserves that are meeting places for native species from both the coast and the Central Valley. Today’s quiet pastoral landscape makes it hard to envision the violent formative flood that may have cut this critical waterway between the Bay and the Central Valley some half a million years ago.
San Francisco’s Fort Funston is perhaps best known for dogs and hang gliders, but its cliffs also host a thriving coastal bank swallow colony.
With stunning views of the Bay and Marin, Richmond’s Point Molate has seen a lot of changes: It’s been a shrimp camp, a huge winery, and a Navy fuel depot. Now the site of a controversial casino proposal, this modest point of land is home to diverse wildlife and some of the East Bay’s last native coastal prairie.
Plate Tectonics And Earthquakes National Earthquake Information Center USGS website providing current data on earthquakes worldwide. http://earthquake.usgs.gov/earthquakes/?source=sitenav USGS Earthquake Hazards Program-Northern California Website providing general and latest quake information, hazard maps, sources of preparedness information, synthesis of current research, and … Read more
On April 18, 1906, a massive earthquake centered just west of San Francisco ruptured the earth from Humboldt to San Juan Bautista. While the more dramatic traces of this 7.8 temblor may be hard to find one hundred years later, the tectonic forces that moved the earth that day are still relentlessly shaping our young and active landscape, carrying us towards another cataclysm in the near future.
All of the familiar landforms we see here in the Bay Area—ridges, cliffs, lakes, and even San Francisco Bay itself—are products of the same titanic encounters between tectonic plates that produce our frequent quakes. Through a geologist’s trained eye, we learn to interpret the signs these forces have left on the land around us.
I was working at my computer at the Bay Nature office in Berkeley the other day when I was interrupted by a short, sharp jolt. I looked around at the others working in the office: “Did you just feel that?” … Read more