Did you know that scientists no longer use the Richter Scale to measure earthquake magnitude? Now, we tend to use the “Moment Magnitude (Mw)” scale, which was built off of the tenets of the Richter scale. 🧪 ⚒️ - ThreadSky

drwendyrocks.bsky.social • 95 days ago

Did you know that scientists no longer use the Richter Scale to measure earthquake magnitude?

Now, we tend to use the “Moment Magnitude (Mw)” scale, which was built off of the tenets of the Richter scale. 🧪 ⚒️

Comments

patoleary.bsky.social•95 days ago

The Richter Scale was always on shaky ground.

saunieindiego.bsky.social•95 days ago

Most excellent. Thank you for posting this. #StayCurious

darkvagabrun.bsky.social•94 days ago

Wow, I did not know this. Thanks for the detailed info.

biobob.bsky.social•95 days ago

Thanks for the update 👍

davidbflower.bsky.social•95 days ago

I didn't know that. You learn something new everyday.

kornygoatweed.bsky.social•95 days ago

Taking a play out of the old pseudoscience (psychology) playbook? Rebrand something established so a new generation of geologists can say "look at us, we did that".

I respect it.

drwendyrocks.bsky.social•95 days ago

Um, no.

nature-ab.bsky.social•95 days ago

📌

jessbortman.bsky.social•95 days ago

Huh! Why?

jessbortman.bsky.social•95 days ago

Oh never mind the post goes on…

asiansean.bsky.social•95 days ago

This is fascinating, I did not know that!

I did a bit more digging, so if anyone is interested to know more about the differences, you can find it here: https://www.usgs.gov/faqs/moment-magnitude-richter-scale-what-are-different-magnitude-scales-and-why-are-there-so-many

scottculkin.bsky.social•95 days ago

I learned this from you, Dr. W. 👊

celestelabedz.bsky.social•95 days ago

Also, the Richter Scale was designed just for the crustal properties of Southern California! Quakes of similar moment magnitude can have wildly varying Richter magnitudes depending on their location. I double cringe when I hear news describe an eastern US quake with the words "Richter Scale."

pennywieser.bsky.social•95 days ago

So prior to the moment magnitude scale, how were east coast and other earthquakes globally reported? Did they have their own scale or use richter?

celestelabedz.bsky.social•95 days ago

I don't know the actual timing of adoption in different places, but you can make Richter-like local magnitude scales that are adapted to other regions. It also didn't go straight from Richter to moment magnitude; there were other scales that worked in different ways developed between the two!

itsthepleiades.bsky.social•94 days ago

In Japan they have their own scale too. Whenever we have like a 6 or 7. The intensity scale is different each time.

morganmp.bsky.social•95 days ago

Great thread! There are many subtleties, as you know. In practice, network seismologists use many different types of magnitudes to describe the size of earthquakes, with moment magnitude being the authoritative (and most accurate) description for large earthquakes.

drwendyrocks.bsky.social•95 days ago

Very true! I wrote a thread about that over on the other site, but alas, it’s gone forever.

dunklewolke.bsky.social•95 days ago

Thanks for the 🧵 something new learnt. Does it mean that the M in the post 👇🏽 ain't Richter scaler but Mw?
https://bsky.app/profile/geofon.bsky.social/post/3lcb7o7eqhf2o

drwendyrocks.bsky.social•95 days ago

Good question! When I see an “M” for magnitude with no letter after it I assume they mean moment magnitude but that can be a bad assumption as there are many different ways to calculate and determine magnitude. Wikipedia does a fair job of outlining many of them - https://en.wikipedia.org/wiki/Seismic_magnitude_scales

eruptionchaser.bsky.social•95 days ago

You would need to ask GFZ directly :-)

When I write a single uppercase M like that to denote a magnitude, you say "M(summary)" - a derived magnitude which is a combination of MLv and mB magnitudes. So amplitude-derived, not a moment magnitude.

GFZ may mean something different. Confusing!

cstark.bsky.social•94 days ago

Here it’s a body-wave magnitude estimate mb, automatically generated by GEOFON computer processing of preliminary seismic data. If the event is deemed important enough, humans will take a look at a more complete dataset and generate (I believe) a moment tensor source model and a moment magnitude Mw.

geohenning.bsky.social•94 days ago

Most of them are initially mb I guess. Haven't found a way to dynamically change in the post which scale is used. I have to look again.

I recommend checking the link to the event page for magnitude updates in general, especially after significant events.

goodbyeyall.bsky.social•95 days ago

That was fascinating!

callipygiancandy.bsky.social•95 days ago

what tell me more

jarediroybal.bsky.social•94 days ago

When I found out we no longer use the Richter scale, it shook me

obsidianfinger.neocities.org•94 days ago

📌

wbuett.bsky.social•95 days ago

What is the advantage of the new scale ?

drwendyrocks.bsky.social•95 days ago

It is outlined in the thread.

alchemist2000.bsky.social•95 days ago

Fun Fact: Most of the general population has no clue as to what the Richter Scale represents. Neither does the media.

drwendyrocks.bsky.social•95 days ago

Thus the reason for thread. Now more people do.

crankycoder.bsky.social•95 days ago

📌

sweetniss.bsky.social•95 days ago

First Pluto, now the Richter Scale!!

comptonscatter.bsky.social•95 days ago

Did you know they took the K/T boundary from us??

THEY TOOK IT! They took the whole damn Tertiary (are they keeping the Quaternary? Why yes, yes they are) and the damn kids on our lawns these days are calling it K/Pg!

* grandpa simpson gif where he complains they changed what "it" was *

sweetniss.bsky.social•95 days ago

ieatdirtforfun.bsky.social•94 days ago

new earthquake news alert

stujackson.bsky.social•95 days ago

I did not know this, thank you ☺️

chrischatfield.bsky.social•95 days ago

Am shook.

andyprentice.bsky.social•94 days ago

Bum, we like Richter Scale. We pretend we know what it means and it sounds cool.

reppocs.bsky.social•95 days ago

@andyrichter.co I am outraged on your family's behalf.

kmgill135.bsky.social•95 days ago

Can we determine the Moment Magnitude of historical earthquakes like 1906 SF earthquake?

drwendyrocks.bsky.social•95 days ago

This is a question for @seismosue.bsky.social

seismosue.bsky.social•95 days ago

(Hi Wendy!). Kathy, the surface rupture and offsets were measured after the 1906 earthquake. That plus knowledge of fault depth lets you estimate moment & moment magnitude directly.

kmgill135.bsky.social•95 days ago

Thanks

drwendyrocks.bsky.social•95 days ago

Thanks Sue!

gimme-danger.bsky.social•94 days ago

@andyrichter.co is this true

sciencewannabe.bsky.social•95 days ago

I think the Seismology community should adopt "Richter Scale" to mean any magnitude scale when talking to the public. Save more specific terms like "Moment Magnitude" for internal discussions. "Richter Magnitude Scale" would fit in the latter category.

drwendyrocks.bsky.social•95 days ago

I disagree. I think it’s fine in general, but it is technically incorrect and words do matter. That being said, there are much bigger fish to fry in terms of combating inaccuracies and misconceptions.

plgc-ontwitterx.bsky.social•95 days ago

🎯

fladdle.bsky.social•95 days ago

📌

looktogod.bsky.social•95 days ago

I feel like I need a printed handout to stick into my old college earthquakes book for the updated info now. Even though that class was decades ago.

looktogod.bsky.social•95 days ago

📌

drwendyrocks.bsky.social•95 days ago

Charles Richter & Beno Gutenberg developed the first magnitude scale in the 1930’s to quantify earthquakes by comparing the size (amplitude) of seismic waves plotted against distance (as calculated from S-P arrival times).

drwendyrocks.bsky.social•95 days ago

But there was a problem. They weren’t able to record all of the frequencies from large earthquakes. The Richter scale did a great job with smaller, local earthquakes but it underestimated large earthquakes.

drwendyrocks.bsky.social•95 days ago

Since that time, more sensitive seismometers, along with faster computers, have enabled us to record & interpret a broader range of seismic signals. These improvements allow us to better determine the energy released by large earthquakes.

drwendyrocks.bsky.social•95 days ago

So now seismologists no longer look at just the amplitudes of seismic waves but instead use much more information contained in the seismogram to calculate what is called the “seismic moment”.

drwendyrocks.bsky.social•95 days ago

The seismic moment, which defines how much force is needed to generate the recorded waves, is defined by factors like the rigidity of the rocks, the area of the fault that slipped, and how far the fault moved.

captainfossil.bsky.social•68 days ago

📌

drwendyrocks.bsky.social•95 days ago

Again, this is a big deal because seismologists can use the Moment Magnitude Scale to measure and describe the size of earthquakes in terms of the energy released, not just the amplitude of the recorded waves.

drgimli.bsky.social•95 days ago

Thanks Wendy. I've known for some time that the RS was not used, but glided over what had replaced it. No more!

rubizco.bsky.social•95 days ago

Oh very cool, i love learning new things like this!

iliketheplanet.bsky.social•95 days ago

I recently started to have an interest in tectonic plates due to home schooling my granddaughter and was really flabbergasted to learn that the whole science only goes back about 120 years. It must have been quite disconcerting in the early 1900's to be told the reality.