Plate Tectonics

On Sat, 11 Oct 1997 18:54:43 -0300, in sci.geo.earthquakes
[email protected] (Dennis Gentry) wrote:

In article <[email protected]>, [email protected] wrote:

Dennis Gentry wrote:

In article <[email protected]>, Al Cooperband <[email protected]> wrote:

On Sun, 5 Oct 1997, David Stinson wrote:

In article <[email protected]>, [email protected] (Dennis Gentry) wrote:

...<snip>...

I brought the plate tectonics question up. Nothing else. As to the answer to your question, mountain raising is a side effect of the interaction of two plates through stress related deformation. Tahoe is in the mountains created through that interaction. Stresses build up along the faults created in the mountain building process and discharge their stress in an earthquake. So mountains on a plate boundary, 200 miles from a plate boundary, or 500 miles or so from a plate boundary can be identified as being built because of stress. Pretty convenient theory I'd say. Can't go wrong with that at all.

Dennis

Sure can't. You do need a sense of scale. And of the concept of zones rather than lines. Plate boundaries cover HUNDREDS OF MILES around the "line" of motion.

...<snip>...

The zone of uplift produced by the collision of India with Asia must extend a thousand miles or more.

Aren't the circumstances there a little different then here in California where both of the plates aren't in a direct collision with each other?

They were in the past. There will continue to be tremendous residual stress from an event that created enough pressure at one time to lift a quadrillion ton batholith (150 cubic miles) 10000 feet. The area of which you speak is formerly volcanic due to the subductions that took place up to about 80 million years ago. The west to east subduction of the Farallon Plate and later on the docking of the Sonoma microplate terrane(the suture of which can be seen on I-80 in the Donner Pass area) created tremendous stress. It uplifted the Sierra Nevada Ranges 15000 feet. You still ask what plate tectonics has to do with an EQ here?

I had heard before some thought of a microplate up in that area but was under the impression that it was still under discussion. But now were saying that the North American plate is made up of several other plates that it absorbed? If the plates have been moving at a constant rate for the last 80 million years, wouldn't the Tahoe area have been up around the Yellowstone area back then?

Read a book. "Assembling California" by John McPhee and also "Basin and Range"