The southern part of the San Andreas fault is overdue for a large earthquake, according to a study in the journal Nature.
This end of the fault has not experienced a major rupture for at least 250 years and is now primed for a release of the built-up tension.
The study by geophysicist Yuri Fialko provides the most precise measurements yet of this accumulated stress.
But scientists cannot predict when another quake is likely to strike.
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Quakes are predicted to occur on the southern part of the fault every 200-300 years. And according to Professor Fialko, the observed movement on the fault is on a par with the maximum amount of shift the fault has ever experienced between quakes.
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more:
http://news.bbc.co.uk/2/hi/science/nature/5105478.stmWell, Okaaaaaaay .... this isn't really news, right? Still,
Nature thought it was significant enough to publish. Apparently this is the most thoroughly quantified asessment to date as to just how much strain has built up. For anyone who's been getting blasé about the "Big One" that never seems to arrive, this is a dash of cold water.