New research highlights the fact that San Francisco is overdue for a large earthquake.
Researchers found four major sections of the San Andreas Fault system in Northern California have stored enough energy to trigger a major earthquake, the Seismological Society of America reported. The recent study estimates how much "creep" occurs along the San Andreas fault system in Northern California.
Fault slip occurs when there is a slow release of strain in the upper part of the Earth's crust; if no fault slip occurs the stress will build up and be released much more quickly in the event of an earthquake, if there is enough creep it could make the next earthquake milder.
"The extent of fault creep, and therefore locking, controls the size and timing of large earthquakes on the Northern San Andreas Fault system," said James Lienkaemper, a co-author of the study and research geophysicist at U.S. Geological Survey (USGS). "The extent of creep on some fault sections is not yet well determined, making our first priority to study the urban sections of the San Andreas, which is directly beneath millions of Bay Area residents."
Understanding the extent of the fault creep system could help researchers gain a better understanding of the risks associated with the region.
The study suggests the faults have accumulated enough strain to spur a major devastating earthquake. There are three creeping faults that have locked areas that have not erupted since the magnitude 6.8 earthquake of 1868 that took place on the southern Hayward fault. Three faults have also most likely built up enough pressure to trigger a major earthquake: "the Hayward (M 6.8), Rodgers Creek (M 7.1) and Green Valley (M 7.1)."
"The San Andreas Fault and its two other large branches, the Hayward and Northern Calaveras, have been quiet for decades. This study offers a good reminder to prepare today for the next major earthquake," Lienkaemper said.
The findings were published in a recent edition of the Bulletin of the Seismological Society of America (BSSA).
