Tidal amplitude on a molten earth?

[xosteve]

If the lithosphere were suddenly removed, would the earthtide amplitude of the mantle be larger than the .25m or so now measured for the lithosphere?

 

[D H]

Except for the liquid outer core and little pockets of liquid magma, the Earth is not liquid. The mantle is solid. Plastic, but solid.

 

[xosteve]

Agreed. I should have avoided the term molten. But the observed solid earthtide is approx. .25m. Since the asthenosphere is several orders of magnitude less viscous than the litho, then with the lithosphere removed, would one expect the asthenosphere solid tide to be greater than .25m?

 

[D H]

By some small amount, sure. That the affect would be at all measurable, I doubt it. People have tried to attribute earthquakes and volcanic eruptions to Earth tides. Those claims are dubious at best. If the lithosphere was a significant impediment to Earth tides their effect on earthquakes and volcanic eruptions would be blatantly obvious.

 

[Shootist]

Except for the liquid outer core and little pockets of liquid magma, the Earth is not liquid. The mantle is solid. Plastic, but solid.

The reason the mantle is plastic isn't because its temperature is below that necessary to melt rock; its plasticity is a result of the enormous pressure of the overlying formations containing it.

One suggests that if the crust were suddenly removed (one does not suggest the mechanism), the plastic mantle would experience catastrophic out gassing, and explosive decompression, resulting in a transition from hot and plastic to hot and liquid (melted), and hot and gaseous.

 

[billiards]

The reason the mantle is plastic isn't because its temperature is below that necessary to melt rock; its plasticity is a result of the enormous pressure of the overlying formations containing it.

It's only plastic over long time scales - it's viscoplastic - it's elastic over the time scales of the elastic waves you get from earthquakes.

Why is it like that? Pressure is a factor, temperature is a factor, chemistry is a factor, and mineralogy is a factor. Putting it all together is extremely difficult, people are doing novel research into this as we read/type.

One suggests that if the crust were suddenly removed (one does not suggest the mechanism), the plastic mantle would experience catastrophic out gassing, and explosive decompression, resulting in a transition from hot and plastic to hot and liquid (melted), and hot and gaseous.

Who's one?

What evidence does "one" have to support their hypothesis?

 

[Shootist]

It's only plastic over long time scales - it's viscoplastic - it's elastic over the time scales of the elastic waves you get from earthquakes.

Why is it like that? Pressure is a factor, temperature is a factor, chemistry is a factor, and mineralogy is a factor. Putting it all together is extremely difficult, people are doing novel research into this as we read/type.
Who's one?

What evidence does "one" have to support their hypothesis?

Both liquid and gaseous outflows will result from crustal ablation/removal. Injections of mafic material, formally semi-solid or plastic, into the created void. Consider, Earth's mantle contains twice the water content of Earth's oceans, not to mention teratons of dissolved CO2 and other volatiles. The result is rather like suddenly removing the top of a shaken soda bottle. The material will exhibit a phase change.

Hellas Basin (mantle melt material (Peridot)), South Pole-Aiken Basin (mantle melt material(Peridot)), Vredefort (igneous province) crater (exceedingly rich platinum/gold/diamond ore bodies), Sudbury (igneous province) crater (largest/richest nickel-iron deposit on the planet).