Replies

I think they're nuts. Yes, quartz is easily fractured, but once it is, it seldom reforms into more pure quartz in great amounts, because the norm is that after fracture other materials mix with the debris from the original quartz fracture.

I've picked up many a rock from deep caves that have quartz mixed with other material that is less hard. It certainly got that way from being in heat high enough to make it molten - as was the material it was mixed with.

But no process I know of would make quartz in molten state separate from other material and become a predominate layer that would explain earthquakes - simply because quartz is among the least materials found at great depth in any of the great open-pit mines around the world. (I've been to several, as a visiting 'rock hound' - begging for 'finds.')

Quartz has a hardness of 9 - just below that of diamond, but it can be shattered just like glass, with great enough pressure. (So can diamonds) But, before I believe all quakes are caused by the presence of quartz, I'd like to see a great deal more of it in the deep mines around the earth - because there just isn't that much that I've seen.

Tectonic plates subverting under another plate causes movement, simply because at 20 miles down, all material becomes molten - allowing that movement. Sorry, quartz just ain't IT when it comes to earthquakes, IMHO.

I see that the National Science Foundation is also covering this and with some neatsy pictures.

Like this one:
New measurements of quartz abundance from EarthScope data show that mountains are quartz-rich (red-orange colors). The Great Plains, Columbia Basin and Great Valley have little or no quartz (blue-green colors).

Credit: Lowry & Perez-Gussinye

Viscous Cycle: Quartz is Key to Plate Tectonics