Wednesday, July 06, 2011
Man’s interference with Colorado River floods that used to regularly flow to the Salton Sea may have “stopped the clock” on a regular series of big earthquakes, setting the stage for a megaquake that could wreck Southern California, according to researchers at Scripps Institution of Oceanography.
A massive 7.5 or larger quake may be the result when the southern San Andreas Fault finally jolts back to life, causing waves of enormous destruction in the Inland Empire and Los Angeles basin, according to a study by Danny Brothers, Debi Kilb and Neal Driscoll published in the scientific journal Nature Geoscience. Kilb and Driscoll were set to detail the study during a morning press conference.
The team examined “displacement indicators preserved in pristine sedimentary deposits, … reconstructed their earthquake history and found evidence for coincident timing between flooding of the ancient Salton Sea and fault rupture,” according to a press release. “Rupture on these newly discovered ‘stepover’ faults has the potential to trigger large earthquakes on the southern San Andreas Fault.”
Driscoll, a geologist, said in a press release that “earthquake simulations reveal that shaking of large metropolitan areas such as Riverside and Los Angeles will be larger if the earthquake propagates from south to north — our research suggests that the Salton Sea stepover zone may provide a trigger for such a propagation direction.”
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