Shaking calculation methods issue's. (Earthquakes and shockwaves.)

[NikHelton]

I'll ask em.

Have you written to them yet?

 

[Ugarik]

I should have mentioned it before but there's another way to calc those feats using potential energy. I came up with this formula a while ago:

PE = V*A^2/(2d^2) * E
V - volume
A - amplitude of oscillations
d - diameter or width
E - Young's modulus of the material

 

[KLOL506]

I should have mentioned it before but there's another way to calc those feats using potential energy. I came up with this formula a while ago:

PE = V*A^2/(2d^2) * E
V - volume
A - amplitude of oscillations
d - diameter or width
E - Young's modulus of the material

What would be the units for these?

Also is there any way to figure out amplitude of oscillations based on Richter Energy?

 

[Ugarik]

What would be the units for these?

SI units for all of these:
V - cubic meters
d and A - meters
E - pascals

Also is there any way to figure out amplitude of oscillations based on Richter Energy?

I don't know.

 

[KLOL506]

SI units for all of these:
V - cubic meters
d and A - meters
E - pascals

Wait, isn't amplitude measured in Hz?

 

[Ugarik]

Wait, isn't amplitude measured in Hz?

No, it's frequency. Besicaly how many times the ground goes back and forth per second.
Amplitude is how much the ground is displaced during the earthquake

 

[KLOL506]

No, it's frequency. Besicaly how many times the ground goes back and forth per second.
Amplitude is how much the ground is displaced during the earthquake

So what is the definition of the term "displaced" here? Is it the deviation in the path of the cracks that take place?

Could you give an example of a calc of shaking a pyramid of Giza? Just to see how the formula works.

 

[NikHelton]

I should have mentioned it before but there's another way to calc those feats using potential energy. I came up with this formula a while ago:

PE = V*A^2/(2d^2) * E
V - volume
A - amplitude of oscillations
d - diameter or width
E - Young's modulus of the material

What width are we talking about? And how does it differ from the amplitude?

 

[Ugarik]

Just the width of the vibrating object.

 

[Ugarik]

Using your calc as an example that width would be base diameter of the mountain which is 734.9 meters. Young's modulus of rock is about 70 GPa.
If we plug everything in the formula above we'll get 97000000 J (assuming 1 cm amplitude)

 

[Ugarik]

The problem is that we PE of 97 megajoules implies the oscillation frequency of 0.017 Hz which doesn't make any sence.

 

[KLOL506]

The problem is that we PE of 97 megajoules implies the oscillation frequency of 0.017 Hz which doesn't make any sence.

That is indeed too low. I remember Nik saying he used a formula from you where he used 30 Hz.

 

[TheUnshakableOne]

I should have mentioned it before but there's another way to calc those feats using potential energy. I came up with this formula a while ago:

PE = V*A^2/(2d^2) * E
V - volume
A - amplitude of oscillations
d - diameter or width
E - Young's modulus of the material

Could this be used say for shaking Mount Fuji violently enough to cause its cave systems to collapse?

 

[NikHelton]

The problem is that we PE of 97 megajoules implies the oscillation frequency of 0.017 Hz which doesn't make any sence.

Maybe then divide 30 Hz by 0.017 and multiply the result by a factor?