Scientists have been trying to find a method to predict earthquakes by detecting its precursors.
California could be hit by a major earthquake in the next two years, a new study has claimed. It is led by Luca Malagnini, the director of research at the National Institute of Geophysics and Volcanology in Italy. His team of researchers studied the Parkfield section of the San Andreas fault and found that quakes happen every 22 years there. The most recent earthquake along this stretch of the fault was a 6-magnitude in 2004, which followed a previous magnitude-6.7 one in 1983, a 6.0 in 1966 and a 6.5-magnitude quake in 1934.
The study, published in the journal Frontiers in Earth Science, concluded that Parkfield is nearing the end of its quiet period and an earthquake strike is imminent.
"We are waiting," Mr Malagnini told Live Science.
Scientists have long been monitoring the San Andreas fault Line that is predicted to be the source of the 'Big One'. It separates the Pacific and North American tectonic plates.
While the faultline is locked in the south of Parkfield, it moves freely in the north, with the plates creeping against one another at a constant rate of 1.4 inches (3.6 centimetres) a year, the outlet further said. Parkfield is a transitional zone between these two plates.
Scientists have been trying for decades to find a method to predict earthquakes by detecting its precursors - strain on rocks or change in permeability under the surface. Mr Malagnini and his team hope to find such clues in Parkfield, known for its recurring quakes.
There have been instances when Parkfield skipped the quakes, but that happened when other nearby quakes changed the stresses in the region. There have been no such quakes this time, so the research team has warned about possibility of a powerful quake.
The September 28, 2004 earthquake shook the area with an epicenter at the town of Parkfield, home to just 37 people at the time.
The quake was felt across a 350-mile (563-km) radius - from Orange County to Sacramento.
Scientists also clocked in 150 aftershocks following the seismic event.