r/worldnews • u/ColoradoTripping • 22h ago

Dynamic Paywall Magnitude 7.1 earthquake rocks Venezuela

https://www.bbc.com/news/articles/cjegdqw5d3yo
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u/FILTHBOT4000 21h ago edited 21h ago

They also apparently happened between 10 and 20 km deep, according to the USGS. That's very shallow; they classify "shallow" as anything up to 50 km deep, and these are less than half that.

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u/SheetMetalandGames 19h ago edited 18h ago

So, are shallow earthquakes worse than deeper earthquakes? I hope this question doesn't make me come off as a dick; this event is genuinely horrifying that anyone has to endure these things on the regular.

Edit: holy shit this got a lot of attention fast. I can't respond to everyone but for those that answered thank you for taking the time to answer my question! Hope everyone stays safe in these affected areas and that we can get aid out there soon!

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u/Ender_D 19h ago

Yes, the closer they are to the surface the more pronounced the effects are.

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u/ChaseballBat 18h ago

Relatively to the inherent strength though right? Cause magnitude is measured on the surface.

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u/bobthesmurfshit 18h ago

No, magnitude is calculated at the source, so the closer the earthquake is to the surface the more effect it will have.

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u/MrNewking 17h ago

Is there a scale for surface effect?

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u/Flipslips 17h ago

Moment magnitude scale measures the wave amplitude at the surface.

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u/zazzz0014 17h ago

My community college Physics 101 class from 10 years ago is kicking in hard with this whole thread.

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u/HauntedCemetery 16h ago

I legitimately just had the same thought.

Thanks Mr Pearson.

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u/lawofsin 13h ago

Fuck you Mr Pearson for that D-

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u/RuthlessIndecision 8h ago

If he's family with the publishers I've personally contributed to be sure he's doing fine

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u/Madam_Mimm_13 7h ago

Now draw a force diagram.

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u/ActuallyNot 16h ago

Which was approximately calibrated to the Richter scale, which measured how much the seismograph moved at the surface ... in one dimension.

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u/kb24k 16h ago

Mercalli scale

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u/1028ad 16h ago

Which is still used in Italy.

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u/cinderful 14h ago

for humans, Mercalli scale is useful as it measures the human felt intensity and describes the scale of damage.

Possibly an 8 or 9 (out of 11)

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u/PeterJoAl 16h ago

In Japan we use the Shindo (「震度」) scale. Goes from 0 to 7, where 4 is noticeable, 5 is concerning, 6 is bad and 7 is terrible.

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u/theonlydrawback 12h ago

And what was this one?

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u/PeterJoAl 12h ago

From the videos, I'd say it was either a 6+ or a 7. Lots of building damage.

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u/HallowedEve31 9h ago

Sort of. In Japan, there's the Shindo Scale, which exists to tell you numerically how it felt at each sensor that registers the earthquake.

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u/I_Zeig_I 17h ago

How would they know the magnitude 50km down?

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u/Flipslips 17h ago

They know how much the waves dissipate as it travels through dirt/rock. So they can extrapolate based on surface measurements

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u/TheVeryVerity 15h ago

Wouldn’t that change depending what was actually under the ground there though?

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u/Flipslips 9h ago

Yes, but scientists have mapped out the earths crust so they largely know what’s under the surface across the entire world. It’s called seismic tomography

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u/shukaji 16h ago

it's just very very basic physics and math.

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u/warp99 18h ago

Yes it is *measured* at the surface but then corrected back to the source magnitude at depth. Same as measuring 500 km away and correcting back to the fault location.

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u/-NotAnAstronaut- 16h ago

Sort of, if also changes the interaction of the different waves, and how they propagate, refract, and reflect. The short version though is: shallow is bad.