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Earthquake!!!

drjeff

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Only certain waves travel the long distances. Here we go

Earthquake have three basic types of elastic waves. Two of the three propagate within the rock itself. The faster of these body waves is called the primary or P wave. this is a compressional wave. P waves are able to travel through both solid rock, such as granite mountains i.e. Cannadien Shield, and liquid material, such as volcanic magma or the water of the oceans. They travel long distances.

The second wave is aslower wave through the body of rock is called the secondary or S wave. As an S wave propagates, it tends to shears the rock sideways at right angles to the direction of travel. It is a transverse wave.Liquids can not propagate this wave.

The speed of P and S waves depends on the density and elastic properties of the rocks and soil through which they pass. The P waves are felt first. The effect is similar to a sonic boom that bumps and rattles windows. This is the wave felt in Brookline. Some seconds later, the S waves arrive with their up-and-down and side-to-side motion, shaking the ground surface vertically and horizontally. This is the wave motion that is so damaging to structures. These do not travel as far either. These waves can also find channels that allow them to travel farther. There is a lot that determines if and where the wave is felt.

The third general type of earthquake wave is called a surface wave, reason being is that its motion is restricted to near the ground surface. Such waves correspond to ripples of water that travel across a lake.

Class over.

Thanks for the info! I think i'm smarter now ;) :lol: :) Although all that talk of S and P waves has my brain in flashback mode to some of my college physics classes :eek:
 

Puck it

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Nice info Puckman !

I took a concentration in geology as an undergrad with the physics major and math minor. I wanted to work as a geophysicist but '86 was not a good time for that. SO went back to grad school to work on Higg Tc superconductors. Geology is still my first passion though.
 

Warp Daddy

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I took a concentration in geology as an undergrad with the physics major and math minor. I wanted to work as a geophysicist but '86 was not a good time for that. SO went back to grad school to work on Higg Tc superconductors. Geology is still my first passion though.

It SHOWS !!! :D Although i never took a geology course i am very interested in it now and may audit a course now just for kicks damn that' would be a hoot -- can u imagine HAVING A 67 YEAR OLD WHACK JOB IN YOUR INTRO COURSE :D
 
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