'Doughnut Hole' Quake Theory Studied

LOS ANGELES, July 19 (UPI) — A new earthquake theory suggests doughnut-shaped patterns of temblors build up over decades to a final large earthquake in the doughnut “hole,” scientists say.

The circular pattern theory, called a Mogi doughnut after the Japanese seismologist who proposed it, may lead to improved earthquake forecasts, the Los Angeles Times reported Sunday.

Recent earthquakes near Eureka and Palm Springs in California and Mexicali in Mexico, combined with large seismic upheavals like the 1989 Loma Prieta and 1994 Northridge temblors, could be precursors to a far larger rupture somewhere in the doughnut “hole,” University of California, Davis physicist and geologist John Rundle and his colleagues say.

They just don’t know exactly where or when, the Times reported.

In the past, experts say, little attention was paid to how faults were connected or whether one earthquake could increase the chances of a quake on another fault.

But now they believe these connections are important and this year’s earthquakes along the Mexican border and near Palm Springs are evidence of the concept.

“Previously we would identify a fault, map it and name it,” Lisa Grant Ludwig, a University of California, Irvine earthquake expert, said. “What we’ve really got here is a network of faults. Maybe that’s what we need to be thinking: more big-picture.”

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Categorized | Earthquakes, Other
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