The existence of slow-slip events, which scientists discovered only
recently, is turning out to be especially important for accurate
forecasting. In a slow-slip event, movement is gradual enough not to
create detectable ground motion, but the energy release can be the
equivalent of a normal magnitude 6 earthquake. The big question is
whether these events may transfer stress to portions of a subduction
zone most prone to a violent jolt, Dieterich explained in a recent talk
on the UC Riverside campus.
He pointed out that scientists reviewing the seismic recordings from
Japan in early 2011 noted a slow-slip event occurred between the main
shock on March 11 and its foreshock.
Analysis of the 1960 Chile earthquake revealed that there appeared to be
a slow slip even between it and its largest aftershock. And dozens of
slow-slip events have been detected in the Cascadia Subduction Zone deep
beneath Washington and Oregon.
So does that increase the chances for another great Cascadia quake?
That's exactly what Deiterich and his colleagues at UCR, Brown
University, Columbia University, the University of Southern California,
San Diego State University, UC San Diego and the US Geological Survey
hope to discern.
Their motives are simple: an increasing fraction of the world's
population lives in regions where great earthquakes occur and is exposed
to high seismic risk as a result. While preparedness is crucial to
dealing with earthquakes, better forecasting of these natural disasters
can save more lives.
Read more:
http://news.discovery.com/earth/nw-earthquake-and-tsunami-threat-120309.html
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