F I R S TP R E V843NEXTLAST

Dangerous Beauty, A Bay Sunrise
In San Francisco it's our faults that make us what we are. The natural beauty of the Bay Area is underlain by some of the most complex and active geology in the world. It is made up of everything from iron and magnesium rocks to sand and gravel. The hills, mountains, rivers, and the Bay itself was created in part by the eleven major earthquake fault lines that run below our feet. That landscape is still being formed as seismic forces drive hills and mountains up and reshape our land.

The first recorded earthquake in California took place in 1769, the most recent earthquake occurred while you were reading this post. California experiences about half a million tremors each year but only about 150 are actually felt and few of those cause any damage. If you're interested, you can track the Bay Area's daily earthquakes at this site maintained by U.S. Geological Survey. The largest California earthquake ever recorded was the Great San Francisco Earthquake of 1906, estimated at between 7.7 and 8.3 in magnitude. That earthquake moved the entire 100-square mile Point Reyes Seashore 15 feet north.

[ MAP E-5 ]