What would exploding a nuclear device on the surface, or even underground (using those fancy ground-penetrating missiles, by the san Andreas Fault do? The unrealistic movie Superman notwithstanding, I have several theories:
Nothing except vaporize a few people within the vicinity. Earthquakes are caused by tectonic plate shiftfs, and exploding a nuclear device doesn’t mean the plate is going to rub against the next one.
Create a big earthquake. Tectonic plates are always rubbing against each other, but don’t move beccause of friction. A nuclear detonation would help the plates overcome their inertia, causing an earthquake of a good magnitude.
Cause THE BIG ONE, with volcanic eruptions from magma coming up thru the damages plate edges.
If earthquakes are the releasing of tension along faults, wouldn’t a backrub work better?
Just kidding.
I remember watching a Nova or somesuch science show, and they had a scientist whose theory was that gradually flooding small portions of the small would cause slippage, inducing many small earthquakes, hopefully preventing a large one from building up. His only worry was that it might be like unzipping the part of North America that holds California to the rest of the continent.
If that’s true, a nuke might simply set California adrift. At the very least, it would cause massive slippage along the fault.
Ahh but you would have to get the Norcal people to agree to do it at the same time as the so cal people :).
Bunnygirl: well the small portion that would be set adrift would probably be much happier, because the hicks, and white trash (and other forms of trash) in the central valley wouldn’t be able to get over to the coast as easily as they do now :). You North American Plate people would still have them though :). (I live on the Pacific Plate side)
Probably not much. But you might facilitate the expression of the next Big One. If it was just about ready to go. And you likely wouldn’t make it any bigger than it was going to be anyway. There is constant tectonic pressure on the (? forget the name of the sub-plate, I want to say Nazca, but I’m not sure and not in the look up mood right now) plate on which the oceanside of So. Cal. exists. It’s being continually, inexorably shoved into the N. Am. craton by the major So. Pacifac spreading zone and has nowhere to go but north or down, and it always doing a little bit of both in the adjustments we experience as both major and minor earthquakes. Every once in awhile there is a substantial correction for this pressure and it is the result of a confluence of geological actions allowing an expression of HUGE accumulations of energy. Your nuke can be but a drop of grease for such. This really isn’t an area I have much to do with, so if you want numbers, I’ll leave it to those so inclined to provide. But my experience is that the earth is quite strong and tackling tectonic remodeling is something we aren’t really up to yet.
So. Cal. isn’t going to just go bon voyage oneday; it’s going to take many of the Big Ones (and be aware denizens of PapaBear Land; they are going to happen) over more time than you and I have got to worry about.
Beatle: Practically any place along the San Andreas should be aware. However, So-Cal people have a little more to be worried about because of the many blind faults in that region (such as the one that spawned the Northridge Quake). The LA basin is also on a lot of sediments mixed in ground water, so it’s more prone to liquifaction. I also hear the San Gabriel Mountains are slowly sweeping in over the LA basin because of the movement in the area. I think (But dont quote me on this), that they move about 5 inches a year? This reminds me, there was a magnitude 5.0 quake in Marin County today around 5 pm PST.
It seems many people think activity on the S.A. fault facilitates The Pac. plate moving away from the N.A. plate. It doesn’t. The Pac. plate is moving North, not West.
IIRC the S.A. fault heads off into the ocean just south of San Francisco. This puts SF on the N.A. plate. Therefore, LA is approaching SF at a rate of 2 inches a year. If my calculations are correct, SF will be a suburb of LA in about 12 million years!
Papa Bear: Nice to see you still around. How long would it take for the plate to move 100 miles to the north? Cause when it does my city will only be 40 miles from SF (I’m about 40 miles west of the SAF).
Doc, I believe the fault you are talking about is a minor off-shoot of the S.A. fault proper. If you take a look at the map at this link you’ll see that the main fault does indeed reach the sea south of SF.
Damn, Papa, could you link to something a little harder to read next time?
I got the visual now, though. LA is west of the fault, SF is east. By moving LA north you will eventually be neighbors. Got it. Unless, of course, the big one hits in the mean time - in which case SF remains pretty much unchanged and you guys become the newest Hawaiian island. Aloha!
The overwhelming majority of people have more than the average (mean) number of legs. – E. Grebenik
::apologies to SDMB residents of CA::