# The Naked Scientists Forum

### Author Topic: Why do seismologists use the Richter Scale?  (Read 7737 times)

#### Johann Mahne

• Guest
##### Why do seismologists use the Richter Scale?
« on: 18/07/2011 16:44:22 »
The Richter scale is always used by the press to describe the magnitude of an earthquake.
Most people have no clue what the scale means.For example the fact that there is a bigger difference in energies as you go up the scale.
Why do the siesmologists not just quote the earthquake directly in terms of energy for the public, and leave the richter scale for their own use?
« Last Edit: 03/08/2011 19:55:25 by chris »

#### Geezer

• Neilep Level Member
• Posts: 8328
• "Vive la résistance!"
##### Re: Why do seismologists use the Richter Scale?
« Reply #1 on: 18/07/2011 18:00:04 »
Reality is a lot more complicated than some people like to think. "Dumbing down" everything only makes it easier for people to pretend that they know what's going on without understanding basic math and science. Personally, I think that is a very bad idea.

#### CliffordK

• Neilep Level Member
• Posts: 6321
• Thanked: 3 times
• Site Moderator
##### Re: Why do seismologists use the Richter Scale?
« Reply #2 on: 19/07/2011 04:33:22 »
Many human perceptions are more logarithmic than linear.

For example, sound perceptions are more logarithmic than linear, with the difference between:
60db --> 70db
&
80db --> 90db
would likely be perceived as similar, when in fact the differences would be exponential.

Earthquake perceptions would likely be similar.  It is also much easier to have a scale from 1 to 10, rather than 1 to 10,000,000,000, although technically stronger quakes are possible, perhaps with a large asteroid impact.  You would have to essentially write everything in either exponential notation, or using prefixes, kilo, mega, giga, etc., which brings you back to the logarithmic scale that is used as one would tend to ignore the number and concentrate on the magnitude of the exponent. (105 vs 109 or whatever based on your favorite units)

It may also be a misnomer that we are using the Richter Scale.  See the notes on the Wikipedia page:
http://en.wikipedia.org/wiki/Richter_magnitude_scale#Details

The Richter Scale saturates with strong earthquakes such as the 2011 Tōhoku Japan earthquake.

#### Johann Mahne

• Guest
##### Re: Why do seismologists use the Richter Scale?
« Reply #3 on: 27/07/2011 18:53:35 »
Quote
Reality is a lot more complicated than some people like to think. "Dumbing down" everything only makes it easier for people to pretend that they know what's going on without understanding basic math and science
This is exactly the atitude by scientists that i'm talking about.Journalists are not going to spend time understanding the richter scale.Why should they?
It's like the recent ecoli scare.Sky News spoke about the ecoli virus for three full days.People listening to the broadcast now think ecoli is a virus.This is not the fault of the journalists it's the scientists who think that everyone knows what this common microbe is.
If an earthquake in January released an energy of 480 metric tons (tnt) and in febuary the same fault released one of 680 Kilo tons then this will explain the differences more clearly then a 5 and 6 on the richter scale.

#### Geezer

• Neilep Level Member
• Posts: 8328
• "Vive la résistance!"
##### Re: Why do seismologists use the Richter Scale?
« Reply #4 on: 27/07/2011 21:47:12 »
Quote
Reality is a lot more complicated than some people like to think. "Dumbing down" everything only makes it easier for people to pretend that they know what's going on without understanding basic math and science

This is exactly the atitude by scientists that i'm talking about.Journalists are not going to spend time understanding the richter scale. Why should they?

Er, how about it's their job? It's not as if it's a big secret how it works, and if they really don't get it, they ought to have contacts they can interview who do. Otherwise, they might want to get another job.

#### CliffordK

• Neilep Level Member
• Posts: 6321
• Thanked: 3 times
• Site Moderator
##### Re: Why do seismologists use the Richter Scale?
« Reply #5 on: 28/07/2011 01:36:37 »
You gain nothing by changing the scale to a linear scale, other than complicating something that doesn't need it.

 Richter Scale Exponential Notation Decimal Notation 0.0 1.0x100 1.0 1.0 1.0x101 10 2.0 1.0x102 100 3.0 1.0x103 1,000 4.0 1.0x104 10,000 5.0 1.0x105 100,000 6.0 1.0x106 1,000,000 7.0 1.0x107 10,000,000 8.0 1.0x108 100,000,000 9.0 1.0x109 1,000,000,000 10 1.0x1010 10,000,000,000

You can use whatever base units you want, Joules, Tons TNT, etc.
And, if you are mixing units, Tons TNT, KiloTons, MegaTons, GigaTons, etc. that just adds another level for confusion.

The numbers are probably only accurate to 2 significant figures, perhaps 3, so there would be no reason to use a 10 digit number when you only need 2 digits.

Finally, the more complicated notation that you choose to use, the more chance for errors and misperceptions.

#### Saille

• First timers
• Posts: 4
##### Why do seismologists use the Richter Scale?
« Reply #6 on: 09/10/2011 00:50:29 »
I like the visual scale that Clifford typed in. I am more visual so just comparing the zeros was helpful.

#### The Naked Scientists Forum

##### Why do seismologists use the Richter Scale?
« Reply #6 on: 09/10/2011 00:50:29 »