A pair of earthquakes that were the largest to rattle Southern California in 20 years could create a domino effect and trigger a big quake along the San Andreas fault.
Researchers say the magnitude 6.4 and 7.1 quakes that hit Ridgecrest in 2010 makes a future quake along the nearby Garlock fault more likely.
If a big enough quake hits that fault, it could trigger the San Andreas too.
Researchers say there's about a one in 87 chance of something like this happening in the next year.
The last major quake along the San Andreas was the 7.9 quake that leveled much of San Francisco in 1906.