The U.S. Geological Survey: The USGS's home page has links to geology, biology, mapping, and water and links to other earth and environmental science sites. http://www.usgs.gov

NASA's Earth Science Program: http://www.earth.nasa.gov/

Terra Server: great air photo coverage of most of California - you need to check this site out! Find Stanford University! Find where you live! Check on the slow but inexorable spread of building and construction into what used to be open space! http://www.terraserver.microsoft.com

Academic Earth Science Departments (a lot of individuals, professors and grad students describe their research or the classes they teach on the web, so you never know what you may be able to find). This site provides an index of sorts. http://www.usd.edu/esci/geodepts.html

This site has nice index maps of recent earthquakes in California and Nevada. An excellent and interesting data base that is updated by the hour!

This site gives you geographically-based information on the location and magnitude of earthquakes around the world. It will also locate any of these recent earthquakes on a map for you.

Color Landform Atlas of the United States provides shaded relief maps of all of the states. These are not as detailed as some, but are extremely useful and give you a useful atlas with which to peruse the topography and landforms of wherever you wish!

World-wide digital topography. A great way of taking a closer look at the world (just the continents), its tectonics and topography.

Global sea topography in color.

Views of the globe. These images were created from the new "measured & estimated seafloor topography" dataset created by Walter Smith, NOAA, and David Sandwell, Scripps Institution of Oceanography.

Examples of various types of imagery, various places, some quite spectacular

http://earth.jsc.nasa.gov/categories.html Click on map for photos of California from space!

Nice overview of USGS's work on the nature of the crust, the San Andreas fault, and earthquakes in the Bay Area. Has nifty 3-D block model of the faults beneath the region, and where the earthquakes are (by Tom Parsons et al.).

A multimedia document compiled from USGS papers with lots of details of the San Andreas fault system and nice photos.

A great and very complete written and illustrated summary of early to recent geologic work on the Carrizo Plain segment of the San Andreas fault (southern California) by Ramon Arrowsmith, previous Ph.D. student here (actually, its part of his thesis!).

Sets or pairs of stereo air photographs of the Bittersweet Canyon proposed trenching site along San Andreas fault north of Carrizo plain. Yep, you can see stereo, and the photos are annotated and descibed in captions (by Ramon Arrowsmith).

Similar to above, from Carrizo Plain, northern Elkhorn Hills

Great set of annotated photos of the southern part of the San Andreas in the Carrizo Plain region, southern California

http://www.monolake.org/ (and links therein) — Mono Lake region

http://www.nps.gov/deva/ - Death Valley National Park site

A great and really slick compilation of mineral and rock thin-section photos with identifying information.