Tremors Predict California Earthquakes

johkir writes "A seismologist at the University of California Berkeley Seismological Laboratory has discovered mysterious tremors deep under the San Andreas Fault that may help predict future earthquakes. The episodes of tremors, which he calls chatter, last from four to twenty minutes and are being recorded from as deep as 40 kilometers beneath the surface -- up to four times the depth of normal earthquakes! These tremors also seem to occur a few weeks prior to detectable surface tremors. Article is published in Science Magazine, but you'll need a subscription, and it is covered in the San Francisco Chronicle and a UC Berkeley press release."

UC Davis

[eikonoklastes]

Researchers at UC Davis have also recently made headlines trying to forecast earthquakes (Press release [ucdavis.edu]). I wonder if we're on the brink of a new understanding of earth's geophysical processes.

Another false discovery, USA stealing credit again

[GISGEOLOGYGEEK]

This type of deep unusual tremor has been known of for several years.

Roughly every 14 months, such tremors occur deep under Vancouver Island. Over a 2 week period, the tremors shift southward towards washington state.

The tremors are related to the subduction of the pacific ocean under north america.

The san andreas fault is a remnant of the subduction zone, where the pacific spreading ridge has already been consumed. This ridge is still a couple hundred km offshore of vancouver island.

The deep tremors on the san andreas are probably caused by the change in strain on the system after the same tremors have occured up here. Yes, the deep tremor cycle did occur like clockwork, as predicted by the canadian pacific geoscience center a few months ago under vancouver island. Several 14 month cycles have been observed.

The weird thing about the tremors is that it represents a rebound in the subduction of the ocean plate. instead of subducting a few cm per year, in two weeks the subduction reverses by about 5cm, and then goes back to the normal.

It is thought that the changes in strain caused by all this may increase the short term chances of the next big quake hitting southwest BC by a large factor.

Anywho, go away, there's nothing truly new to see here, it may not have been observed so far south before, but it is not a discovery of a new type of geologic activity, the Canadians already documented it, which maybe the media would have realized had they bothered to look outside your borders for something other than the injustices of Iraq.