There is a Hole in the …
Wednesday, July 21, 2010 2:58:42 PM
“The Mogi doughnut hypothesis, developed by a Japanese seismologist, holds that earthquakes occur in a circular pattern over decades, building up to one very large temblor in the doughnut hole.”
In Terra Daily a day later they came up with this comment:
“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.”
To call it a “new theory” may not be quite correct as the Japanese seismologist K. Mogi suggested the idea back in 1969, which isn’t exactly last week.
The concept holds that earthquakes sometimes occur in a circular pattern over decades -- building to one very large quake in the doughnut hole. The idea behind the doughnut is relatively straightforward: Earthquakes in California are basically caused by tectonic movements in which the Pacific plate slides northwest relative to the North American plate. As the plates move, stress builds up along both sides of cracks in the Earth's crust, as if a giant sheet of peanut brittle were being shoved in two directions. Tectonic stress will first cause ruptures on the smaller faults, because they need less pressure before they break and thus produce small earthquakes. When they do rupture, the tectonic pressure gets transferred somewhere else, moving along like a crack in a windshield. Ultimately, the stress moves closer to bigger faults that need more pressure to erupt, thus creating larger and larger earthquakes until the "Big One" happens.
Take it for what it is: Just another unproven and not universally accepted hypothesis (and not even new). Why shouldn’t random earthquakes sometimes randomly create a certain recognisable pattern (circle, square, triangle …).