Yes

No. while there is a chance that an earthquake could effectively sink the state (west of the fault line), there is also a chance that things could fall up. the plate movement is to the east (edit. i was tired and put west). The more likely thing is that any big earthquake that'll happen anytime in the reasonable future would just push the west coast closer to the east coast. edit: yeah, i'm wrong. well sorta.

A single earthquake will not split California from the rest of the continent. A whole series of quakes will eventually split the westernmost sliver off. That portion of California that includes the coastal portions from the Gulf of California almost to San Francisco Bay and Baja California is actually on the Pacific Plate. This plate is sliding northward past the North American Plate along the San Andreas Fault at a rate of a few centimeters per year. Eventually this movement will separate this part of California and turn it into an island off the coast of Northern California. As this island continues northward, eventually it will crash into and become part of Alaska. However, all of this will take millions of years to accomplish. So, it is not something that we really need to worry about, not that there is anything that we can do about it anyway. David, Despite what Hollywood has portrayed, there is not that much total movement in an earthquake. Even the most powerful quakes only generate a few tens of feet of movement along the fault line. That is not enough to split that portion of California that is west of the San Andreas away from the rest of the continent in one single earthquake. I think that you should take a look at http://www.uwgb.edu/dutchs/pscindx.htm . The author of this site does some fairly extensive analyses of the junk that passes for science in movies. Especially look at his analysis of "10.5". **************** "David Hedrick: If it were seperated by tens of feet would it not be seperated?" You don't understand how movement along a fault occurs. When movement occurs, the rocks on either side of the fault slide past each other. The movement is either side to side, up and down, or both. The rock along the fault don't pull apart. In the case of the San Andreas fault, the rocks to the west are slowly moving northward while those on the east side are moving to the south. In order to separate that portion of California that is west of the fault from the rest of the continent, it must slide off the continent to the north. That means that it must move over 400 miles. Addendum: David in places were the crust is pulled apart you get volcanism. As the plates pull apart, pressure on the underlying asthenosphere is reduced allowing it to melt this produces basaltic magmas which produce volcanism along such boundaries. This fills in the gap between the plates that are pulling apart. A very good example of this can be seen in East Africa. Horn of Africa is pulling away from the rest of that continent. The amount of stretching that has occurred there is on the order of tens the hundreds of miles (not just a few feet) and the horn is still attached to Africa. Additionally, This stretching has not all occurred at once, but as a series of earthquakes over millions of years. The San Andreas fault has no significant volcanism associated with it. Over a century of studies of the fault show no evidence of the type of movement you propose. It's not happening and it is not going to. I am not trying to be insulting, but you do not know whereof you right here. A mere movement of just a few tens of feet in any direction along the San Andreas fault will not separate the coastal portion of Southern California from the rest of North America. Trust me on this. I have a Master's Degree in Geology and all the education that went with that backing me up on this. **************** "David H: All that education and you can't see where you contradict yourself? Doesn't happen, cant happen, this is how it happens..." "There is none so blind as them that will not see."