A US geophysicist has set the scientific world ablaze by claiming to have cracked a holy grail: accurate earthquake prediction, and warning that a big one will hit southern California by Sept 5.

The UCLA team — made up of US, Japanese, Canadian, European and Russian experts in pattern recognition, geodynamics, seismology, chaos theory, statistical physics and public safety — says it has developed algorithms to detect earthquake patterns and has already successfully predicted two major quakes.

Another expert says the San Andreas fault is about to enter a new and violent period of shaking.