Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: EvaH on 30/03/2021 17:05:56
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Douglas wants to know:
Does the energy released from an earthquake follow the Inverse Square Rule (or something similar) in relation to distance from the epicentre?
What do you think?
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Does the energy released from an earthquake follow the Inverse Square Rule
The Inverse Square Rule applies to energy radiated equally in all directions in a 3-dimesnional volume, from a point source.
Most Earthquakes consist of a slip along a fault line, so the source is 2-dimensional, rather than a point.
- And the earthquake waves don't radiate equally in all directions.
- But if the Earthquake is far away (so it looks like a point from where you are), the strength of the earthquake shock does reduce with distance.
There are some special cases:
- If your home is built on loose and/or wet sediment, this can accentuate shaking and cause more damage to buildings, or liquify and swallow buildings.
- If you are located diametrically opposite the earthquake location on the Earth, the liquid core absorbs the "sideways" earthquake waves, leaving a bit of a shadow on the other side.
- Much of the damage from Earthquakes comes from Tsunamis. Because the ocean is a thin 2-dimensional skin on the Earth, the Earthquake energy spreads out like 1/distance, not like 1/distance2. This means that tsunamis can spread disaster further than the earthquake waves.
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Hello Douglas!
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Evan has pretty much Explained it All!
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But if you wish to know a bit more about Seismic Waves, here's a Link which might be a good read.
https://www.britannica.com/science/seismic-wave
P.S. - It would be Wise to know what category of Risk your locality falls under, there are separate earthquake prone zones categorised according to risk levels.
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Also just a simple rehearsal of the Act with your whole family & pets would Really help if it ever strikes.
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Tc!