How to calc a character shaking a mountain?

[GraveDigger84]

I already made a calc for a feat of this nature here but now I’m unsure if I did it right

Primary calc: https://vsbattles.fandom.com/wiki/User_blog:GraveDigger84/Enceladus_shakes_Mount_Diablo

Secondary calc: https://vsbattles.fandom.com/wiki/User_blog:GraveDigger84/Percy_shakes_Hubbard_Glacier

So I had a few questions about using the Mercalli scale to calc shaking things

1. Formula? I thought it was 0.5*(Mass)*(Velocity from Mercalli scale)^2 = Energy in Joules but then I saw other users computing it a different way, including using mass instead of volume.
2. Use case? In the cases I showed where either a mountain or glacier is being shaken by a character striking it (the second one might be caused by powers but eh), is this formula good to use in these cases?
3. Units? This tends to trip me up sometimes. M^3 for volume, kg for mass, that’s all fine right? And when I’m bringing in densities that come in g/cm^3, can I compute the mass in grams and then convert it later? Also for mountains, what material do I choose to get the density?
4. Velocity: if the graph for example on intensity IV says 1.41-4.65, which one do I put in the formula? And let’s say I used 4.65, do I have to input it as .0465? Since that’s what I saw other people doing. Also, how do I decide which velocities to use?

 

[GraveDigger84]

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[GraveDigger84]

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[GraveDigger84]

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[GraveDigger84]

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[The_Fiend888]

1. Formula? I thought it was 0.5*(Mass)*(Velocity from Mercalli scale)^2 = Energy in Joules but then I saw other users computing it a different way, including using mass instead of volume.
2. Use case? In the cases I showed where either a mountain or glacier is being shaken by a character striking it (the second one might be caused by powers but eh), is this formula good to use in these cases?

Yes, the formula is correct. I don't quite understand what you mean in the second sentence, but in the formula we use mass, not volume.
This formula is usually used when the vibration is caused by physical blows, when there's no evidence that the shaking is an earthquake, and when the shaking thing is not connected to the tectonic plates. So it seems to me that this would be acceptable in both cases.

3. Units? This tends to trip me up sometimes. M^3 for volume, kg for mass, that’s all fine right? And when I’m bringing in densities that come in g/cm^3, can I compute the mass in grams and then convert it later? Also for mountains, what material do I choose to get the density?

Yeah.
It's not a big deal as long as you do it right. But it seems to me that you made a mistake in your first calc. If I remember correctly, to convert m3 to cm3, you have to multiply it by ten to the six power, but you multiplied it by ten to the seven power.
When trying to find the weight of things like mountains, they usually use 2700 kg/m3, which is the density of the upper tectonic crust, rock and soil. But if this mountain is volcanic and mostly basalt, I don't think this would be a problem.

Velocity: if the graph for example on intensity IV says 1.41-4.65, which one do I put in the formula? And let’s say I used 4.65, do I have to input it as .0465? Since that’s what I saw other people doing. Also, how do I decide which velocities to use?

In such cases we usually use either the average of the two speeds or the low-end. And yes, you need to convert cm/s to m/s.

 

[GraveDigger84]

Yes, the formula is correct. I don't quite understand what you mean in the second sentence, but in the formula we use mass, not volume.
This formula is usually used when the vibration is caused by physical blows, when there's no evidence that the shaking is an earthquake, and when the shaking thing is not connected to the tectonic plates. So it seems to me that this would be acceptable in both cases.

Got it, thanks

Yeah.
It's not a big deal as long as you do it right. But it seems to me that you made a mistake in your first calc. If I remember correctly, to convert m3 to cm3, you have to multiply it by ten to the six power, but you multiplied it by ten to the seven power.

You are correct. It should be 3.74e15, not e16. I'll adjust the calc accordingly.

When trying to find the weight of things like mountains, they usually use 2700 kg/m3, which is the density of the upper tectonic crust, rock and soil. But if this mountain is volcanic and mostly basalt, I don't think this would be a problem.

Well the mountain itself isn't mainly basalt, it's created by the compression and uplift of plates. Only the upper portion is more volcanic in nature and even then contains a lot more materials than just basalt. I guess the density you gave would be better then?

In such cases we usually use either the average of the two speeds or the low-end. And yes, you need to convert cm/s to m/s.

Will do

Appreciate the help