[IG_Semmelweiss]

Lol, now you are making stuff up.

Most local magnitude scales are

>>> determined from the logarithm of the amplitude of waves recorded by seismographs. Adjustments are included to compensate for the variation in the distance between the various seismographs and the epicenter of the earthquake[1].

So unless people in the East have seismographs located farther underground with scientists staffing them really deep underground -for reasons beyond me- "Shallow depth" is irrelevant.

Also, there's no such thing as a "feels like X magnitude" earthquake [2]

[1] https://en.wikipedia.org/wiki/Richter_scale

[2] https://earthscience.stackexchange.com/questions/22348/what-...

[jpalawaga]

From your stack overflow link:

>"Feels like" is measured on seismic intensity scales such as the Mercalli scale. These measure the peak acceleration or velocity at a given point, or the damage done by the earthquake. Intensity is influenced by many things, such as the depth of the earthquake, the distance to the ruptured section of the fault, and the local surface material.

https://en.wikipedia.org/wiki/Modified_Mercalli_intensity_sc...

NYC has had 5.x earthquakes that have caused e.g. chimneys to collapse, something unheard of in california.

[IG_Semmelweiss]

The Mercalli scale you cite is defined in roman numerals.

The parent posted decimals.

As you said, they are not the same thing.

[jpalawaga]

Are you intentionally being pedantic? The point doesn't have anything to do with whether decimals are used or if conversions are direct. The point is that a 4.8 earthquake can feel different given numerous factors. The Mercalli scale attempts to capture the surface-level disruption, rather than the inherent force at the site of the quake as the Richter scale does.

Depth IS relevant to how an earthquake feels (as opposed to your assertion it isn't)--even the usgs publishes depth information. If you go back to the stack overflow link you posted, you can clearly see that a lower magnitude earthquake can be much more damaging.

The point is, richter measurement doesn't tell the whole story, and yes, you could say that a 4.8 would feel like a 6.0, even if we don't have a good way beyond the mercalli scale of discussing that. That's because the original output energy is only partially relevant to how someone experiences a seismic event.

tl;dr: your pedantic assertion that there's no conversion between the two is correct. your assertion that depth doesn't matter for feeling quakes is incorrect.

[adolph]

Yes, the Roman geologists did not use decimals but fractions. "S···· or S∷ | Dextans, dextantis or decunx, decuncis" would be the equivalent of .8 since they used "a duodecimal rather than a decimal system for fractions."

https://en.wikipedia.org/wiki/Roman_numerals