Abstract
Beside plate tectonics, isostatic rebound may be a main contributor in the seismogenic process in Fennoscandia. Extensional horizontal strain, presumably related to land uplift, calculated from mathematical modeling, geodetic data and curvature of uplift, show higher values than compressional horizontal strain, related to ridge push, estimated from sedimentary deformation in the basins surrounding the shield. The location of the current seismicity of central and northern Fennoscandia and the sites of large boulder caves near the Bothnian coast of central Sweden, show high correlation with the maximum curvature of uplift at present and late-glacial time, respectively; the caves may have been created by large earthquakes at the last phase of deglaciation.
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jmnemonic wrote: 'mass goes away here' and then that mass goes....where? And does it have any effect when it arrives?
scas wrote:I know i've said it before, but redistribution of large masses of polar and glacial ice are sure to affect the Earth's wobble...
SeaGypsy wrote:Greenland's ice mass has to be significant enough to change the axis. I guess how suddenly this melts will affect the wobble. Has anyone done the maths on where the axis is with Greenland's ice sheet melted?scas wrote:I know i've said it before, but redistribution of large masses of polar and glacial ice are sure to affect the Earth's wobble...
The scientists’ model took into account the West Antarctic ice sheet’s gravitational pull on nearby ocean water
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Second, researchers found that if the weight of the ice disappears, the tectonic plate that it has kept buried beneath it will rise, forcing water to flow into other areas.
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Finally, the melting ice sheet also would change the way the earth wobbles as it spins, according to the study. This would redistribute the ocean’s depth, transferring seawater from areas in the southern Atlantic and Pacific oceans to the southern Indian Ocean and areas around North America.
“When you remove the mass of the ice, the earth will change its axis,” says Holland of New York University. “Big chunks of water will move to the equator” from Antarctica, he adds.
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The results of the study startled even its authors. “I knew that the gravitational effect on meltwater would be important, but I was very surprised the contributions from the other two effects were just as large,” says Mitrovica.
SeaGypsy wrote:scas wrote:I know i've said it before, but redistribution of large masses of polar and glacial ice are sure to affect the Earth's wobble...
Greenland's ice mass has to be significant enough to change the axis. I guess how suddenly this melts will affect the wobble. Has anyone done the maths on where the axis is with Greenland's ice sheet melted?
Where was the axis last time Greenland was ice free? How radical a melt would it take to cause catastrophic wobble? I can't recall who wrote it but I remember about 20 years ago someone predicting a radical wobble caused by ice melt triggering mega storms with 500 MPH winds. To my mind the earth rotation axis shift and wobble are the most likely globally devastating consequences of melt.
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