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In my on going research of hypertherical large humanoids -- and large creatures in general, I'm now looking towards somewhat of a trope for giant creatures -- tremours.

Would a large, humanoid creature, of say, 50 feet, when simply walking, cause noticeable tremors?

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    $\begingroup$ You'll have to define "noticeable" first. 20+ years ago I had a mystery--my computer would always wake up as I approached it. The culprit turned out to be a trackball sitting on a pull-out surface on the desk. This was on the second story, my footsteps (even on carpet) were enough to vibrate the mouse enough to be recorded as movement. $\endgroup$ – Loren Pechtel Apr 30 '17 at 21:13
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    $\begingroup$ I think a mass would be important too, sure someone could scale up a human and work it out but if you added that information first it might people not have to work out what sort of forces they were talking about. Also what surfaces are we talking about? Sandy beaches, dry rocky planes, grassland, forests. It might not be a big factor but it might help to know. $\endgroup$ – Lio Elbammalf Apr 30 '17 at 22:11
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It depends on countless factors, so you can really do anything you like.

You can get tremors from a footstep two ways:

  • Waves emitted from the step
  • Waves emitted because of non-linear effects within the ground.

The waves emitted from your steps you can actually feel on human scales. Just go to the 2nd story of a house and walk around. You'll hear the waves emitted when you step. In fact, if you can find an industrial building, many of them have very large distances between supports (so you can have large open work areas). I work in one where there's points that you can hop up and down at and people can feel the vibrations in the floor 20 feet away.

These effects are very dependent on how the creature chooses to step. Go to your 2nd story building and clomp around for a bit. Then try to walk like a cat stalking its prey. The kind of stepping you do dramatically changes what tremors you might find.

The second effects are the non-elastic effects which occur when you push the ground too far. In our 2nd floor house example, these are the creaks and squeaks that the floor emits when you push on it. Naturally, as you've noticed that some floorboards creak more than others, this is very dependent on the exact terrain. A nice granite mountain could withstand a much larger creature than, say, wet sandstone.

Of course, with this many variables you can get all sorts of interesting effects. Trees can cause tremors, for instance. In fact, they can be downright creepy.

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  • $\begingroup$ Wouldn't larger feet also reduce the local pressure and thus reduce the degree of tremors in the material? $\endgroup$ – a CVn Apr 30 '17 at 19:54
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    $\begingroup$ @MichaelKjörling That's a complicated one without knowing the exact dimensions of the creature. However, there will be yet another square-cube law issue here, for the surface area of the feet will scale by the square, while the mass will scale by the cube. $\endgroup$ – Cort Ammon Apr 30 '17 at 20:03
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    $\begingroup$ Square-cube law, I hate you! You're always there to ruin the easy going on the party! ;-) $\endgroup$ – a CVn Apr 30 '17 at 20:13

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