List Of 4 San Francisco Bay Area Faults Ready To Rupture In Major Earthquake
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SAN FRANCISCO (CBS SF) -- Four areas of the San Andreas fault system in the San Francisco Bay Area have accumulated enough energy to produce major earthquakes, a new study finds.
The study estimates the Rodgers Creek, northern Calaveras and southern Green Valley faults are long overdue for a major earthquake. Those three faults have not ruptured in a major earthquake of at least a magnitude 6.7 since the reporting of earthquakes by local residents. The southern Hayward fault, which produced a magnitude 6.8 earthquake in 1868, is also past its due date.
The study published Monday in the Bulletin of the Seismological Society of America proposes how much creep, or movement that involves a gradual change in land shape, occurs on each section on the 1250-mile-long San Andreas fault system. Enough small movements on a fault can diminish the potential size of its next earthquake.
"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, co-author of the study and geophysicist at U.S. Geological Survey. "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."
The researchers studied past earthquakes of individual faults to calculate the timing and size of future earthquakes.
"The San Andreas Fault and its two other large branches, the Hayward and Northern Calaveras, have been quiet for decades," Lienkaemper said. "This study offers a good reminder to prepare today for the next major earthquake."
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