User talk:Mike03858

While much discussion continues on the effects of climate change on weather and sea level, I hear very little or none about the potential effects of continental rebound (glacial isostatic adjustment).

Consider this: Arctic ice is mainly found floating in the sea, other than in Greenland and in northern parts of Russia and Alaska. Excepting Greenland for the sake of this discussion, when the arctic ice melts it doesn't contribute much to sea level rise because it's simply two phases of water (solid and liquid) in the same container, if you will. And there is no continental rebound because there is no continent beneath the melting ice to 'rebound' off the Earth's mantle.

On the opposite pole, however, the antarctic ice averages approximately 3 miles in thickness, and mainly rests atop the continent Antarctica. When this ice melts and flows into the ocean, it adds to the volume of the oceans while not increasing their 'container' volume significantly. Thus, Antarctic ice (and any arctic ice not already in the ocean) will fill the existing 'container' and result in measurable sea level rise.

But our subject here is continental rebound, which is the vertical rise of land masses that are depressed by the huge weight of ice sheets as that ice melts. The process is known as isostasy. One of the possible impacts of global warming-triggered rebound may be more volcanic activity in previously ice-capped areas.

But the impact of continental rebound on increased seismic activity may be more important in the near future. That is because as the ice load on the Antarctic continent rises, the Antarctic tectonic plate will readjust along its borders. According to the theory of plate tectonics, plate-plate interaction results in earthquakes near plate boundaries. And according to Wu & Hasagawa, the rebound stress that is available to trigger earthquakes today is of the order of 1 MPa, though that figure may be 20 to 30 MPa or more on Antarctica.

According to the Mohr–Coulomb theory of rock failure, large glacial loads generally suppress earthquakes, but rapid deglaciation promotes earthquakes.Studies have shown that the uplift has taken place in two distinct stages. The initial uplift following deglaciation is likely to be near-instantaneous on a geological time scale due to the elastic response of the crust as the ice load is removed. After this elastic phase, uplift proceeded by slow viscous flow so the rate of uplift decreased exponentially after that.

But during the elastic phase, we can expect rapid readjustment of the Antarctic plate along its borders - which comprise the edges of seven other tectonic plates. All of these plate-plate interactions around Antarctica take place at or below the sea floor.

Underwater earthquakes and resulting underwater landslides often cause Tsunami. So, in conclusion, I propose that climate change, vis-a-vis melting of the Antarctic ice cover, will cause result in a sharp increase in earthquakes and associated Tsunami. And this result has the potential to take place soon.

MRG Mike03858 (talk) 12:19, 28 December 2012 (UTC)