The Other California: Come to California and You Could Die a Fiery Death!!

Ask people about volcanoes in the United States, and I suspect they will mention Hawaii, Washington, Oregon, or Alaska. Ask about California, and most people will recall perhaps two volcanoes found in our state. What many folks don't realize that California is riddled with volcanoes, literally hundreds of them, from one end of the state to the other. Of the eleven geomorphic provinces, recently active volcanoes can be found in at least seven. My next exploration of the "Other California" will involve some of these fascinating and possibly dangerous places (I thought I use a cable-channel language: come to California and you could die in a violent eruption!!). From a more academic point of view, California is one of the best places in the world to study volcanism. The state has nearly every kind of volcanic landform there is, due to the multiple plate tectonic settings in the state. To the south and east, the state is diverging, stretching apart, allowing partial melting in the upper mantle. To the north, plates converge to form the Cascadia subduction zone, forming massive stratovolcanoes. Some volcanism even occurs along the parts of the San Andreas fault system, a transform boundary.

Today's picture shows the largest volcano in the state of California. Today's question: what volcano is it?

By the way, come and visit California. We're friendlier than you think, and chances are you won't die a fiery death in a volcanic eruption. They don't happen that often, and generally give lots of warning...

Large Quakes in Gulf of California

Some large quakes within the Gulf of California a short time ago, with the largest preliminary magnitude at 6.9. They all happened within a few minutes of each other, so I expect the reported magnitudes will change as they sort out the data. The closest town is Santa Isabel in Baja California, 76 miles away. A 5.8 shock preceded the 6.9 event, which was followed by aftershocks at 6.0 and 5.0 magnitude.

The Gulf of California is the result of divergence, where Baja is sliding northwest and separating from the Mexican mainland. The movement of Baja is intimately related to motion on the San Andreas fault in California, as Baja and all the lands in Alta California west of the San Andreas are part of the Pacific Plate, which is shifting northwest at around 2 inches a year.

It's a good reminder that California is earthquake country, and that enough stress has built up on different sections of the San Andreas fault to produce major quakes. You can read lots more about earthquake hazards at http://earthquake.usgs.gov/.