It's a well known fact that the state of California lies on the San Andreas Fault, making it extremely prone to earthquakes. Earthquakes being what they are, there is always bound to be a powerful earthquake to arrive once in a while, as movies can attest to.

So when is the big one coming? New data from the 2007 Working Group on California Earthquake Probabilities say that the next big earthquake will arrive within the next 30 years. According to their data, it's a 99.7% guarantee.

Their data says that an earthquake with a magnitude of 6.7 or larger will hit within that time. The chances of a magnitude 7.5 earthquake hitting within that period is 46%, and will more likely happen in the southern half of the state.

Magnitude 7 earthquakes are known to be devastating. If you happen to live in California, you may want to consider looking for some hills to head for once the big one hits.