Scientists have been tracking the movements of the four faults found within the San Andreas system. The faults appeared to be primed for a huge rupture which could then result to an earthquake that has a magnitude of 6.7 or higher.
The faults have been identified as the Hayward which is between San Jose and Suisun Bay; the Calaveras which spans from Hollister to Danville; the Green Valley Fault which is near Fremont and Richmond; and the Rodgers Creek Fault which is found in southern Sonoma County.
Among these four faults is the Hayward Fault which is most likely to shake within the next 30 years.
"The Hayward Fault is the one that affects the most people and infrastructure," said Jim Lienkaemper, a research geophysicist at the U.S. Geological Survey.
The last time that the Hayward Fault had ruptured was in 1868 wherein it reached an estimated magnitude of 6.8. From 1609 until 1745, other major earthquakes have been recorded from the other faults. These would include the 1609 rupture on the Green Valley Fault; the 1740 earthquake along the Calaveras Fault; and the 1745 rupture found on the Rodgers Creek Fault.
Since the last time that an earthquake or a rupture had occurred was more than 146 to 405 years ago, geophysicists are predicting that the faults are more than ready to break into a major earthquake again anytime.
"Given how long ago they had their last earthquakes, they are more than ready to produce a major earthquake again now," said Rolan Burgmann, a geophysicist and expert on crustal deformation at UC Berkeley.
Lienkaemper and his team have been studying the movements of the faults along Northern California for several years. They noted that the faults moved at a few millimeters each year. However, the extent of all those movements that have occurred through the years can be seen on curbs and on the road which bear major cracks.
The group had estimated that the next major earthquake could have a magnitude of 6.9 which is comparable to the Loma Prieta earthquake that occurred 25 years ago. It was a devastating earthquake that left 63 people dead and $6 billion in total damages. It is predicted that the Hayward Fault and the Calaveras Fault could rupture at a magnitude of 6.8. The other two faults, Rodgers Creek and Green Valley could reach a magnitude of 7.1.
Experts are hoping that the new study will make individuals, governments and businesses find a way to redesign older structures in order to make them safer. Home foundations, particularly those made from rigid substances, must be reinforced.
