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New Study Shows Deep Mantle Flow and Earthquakes
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by
Mitch Battros - Earth Changes Media
Earth is made up of a solid inner core, surrounded by a
liquid outer core, in turn covered by a thicker or more
viscous mantle, and ultimately by the solid crust
beneath our feet. The magnetic field is generated by the
motions of the liquid iron alloy in the outer core
beneath Earth's crust. These motions occur because the
core is losing heat to the overlying solid mantle that
extends up to the crust on which we live.
*Interview
with Professor Gary Glatzmaier at bottom
The mantle itself is also in motion. This mantle motion
is responsible for the drifting of the continents at the
surface - and responsible for earthquakes, volcanoes,
and temporal changes in the climate.
In the past decade or so, researchers have focused on three possible mechanisms driving Earthquakes. One is variations in gravitational potential energy, another is changes in thickness of the Earth's crust along the Intermountain Belt and the third is changes in strength of the lithosphere; that is, the crust and upper mantle. 
"In continental
interiors, we know little about the forces that drive
the Earthquake cycle," says Utah State University
geophysicist Tony Lowry. "We rely mostly on the history
of past Earthquakes to assess hazards. But, because
seismic observations cover only a tiny fraction of the
time between the largest Earthquakes, we can easily miss
important parts of the story."
Using new seismic and GPS
data available from the massive NSF-funded Earthscope
array across the western United States, the researchers
looked at these observations simultaneously and found
some surprises. "We've explored various aspects of how
and why rocks break and flow, but this is the first time
we've recognized the importance of deep mantle flow,"
says Lowry. "This developing model gives us a new tool
for understanding what makes Earthquakes tick."
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Professor Gary A
Glatzmaier - Solar Physicist - Gary's recent
research has focused on the Earth's core. He produced
the first dynamically-consistent computer simulations of
the geo-dynamo, the mechanism in the Earth's fluid outer
core that maintains the geomagnetic field. The
simulations span several millions of years, using an
average numerical time step of 15 days. At the surface
of the model Earth, the simulated magnetic field has an
intensity, an axial dipole dominated structure, and a
westward drift of the non-dipolar structure that are all
similar to the Earth's. Website:
http://www.es.ucsc.edu/~glatz/
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