Talk:Richter scale/Archive 1

Untitled

Boffman 21:16, 25 March 2006 (UTC) March25 - reverted to old version due to vandalism.

TNT energy table

What's the difference between Approximate TNT for Seismic Energy Yield and TNT equivalent of example? The numbers are significantly different in certain cases, and I'm not sure why we need both columns. -- nae'blis _(talk) 16:20, 7 June 2006 (UTC)

right, it's reproduced a lot of junk but the orders of magnitude in ergs don't add up. I agree w

Not sure if that table isith this table http://www.cwp.mines.edu/~john/empirical/node7.html

The TNT equivalents don't add up either: 6.0=1MT contradicts 7.0=50MT (surely it's 32MT?), also 8.0 = 1GT contradicts 9.0=5.6GT (did they mean 8.5=5.6GT?) and 9.3=32GT (did they mean 9.0=32GT?) HairyDan 21:45, 25 August 2007 (UTC)

Good observation. I came here to comment on this myself. The Seismic Yield is the percent of an explosion converted to actual ground waves. This is much less than the blast itself (eg 1%), but it of course depends hugely on where you put the explosives. Should the table quote seismic yield or just raw total yield when making comparisons? I dunno. On the one hand seismic yield is a very fuzzy concept. On the other, it's kind of unfair to compare the felt force of an earthquake to just the theoretical energy of a bomb. After all, the actual energy of rock sliding past itself is also much greater than what percolates up to the surface. —Preceding unsigned comment added by Alex dubinsky (talk • contribs) 09:10, 27 July 2008 (UTC)

Richter Magnitudes

The table in this section has a column heading "Retro Earth magnitudes". This term does not appear anywhere else in the article, and I can't find a definition of it elsewhere (using Google). Either it needs to be changed to "Richter magnitude" or else "Retro Earth magnitude" needs to be introduced and defined before the table.

"estimate for a 10 km rocky bolide impacting at 25 km/s"

The TNT equivalent given here disagrees with the value given here by a factor of one-hundred.

If I've done the math correctly (?) than if the Tsar Bomb was 50 megatons it should have a Richter Magnitude of more than 10.

2/3*(log((4.2*10^12)*50,000,000)-4.8) = 10.348

So why is it catagorized as around 7? The Tsar Bomb link even discusses 4.2 megaton underground nuclear tests as resulting in siesmicity of around 7 -- so something's off about this table. 24.16.93.26 21:52, 18 January 2007 (UTC)

Rocky Bolide Math

Crunching the numbers:

A 10-km diameter bolide, with a density of 5 g/cm^3 (or 5 times the density of water. Iron is 7.86 g/cm^3, the Earth is 5.5), has a mass of about 2.6*10^12 g. Traveling at 25 km/s, the bolide would have an energy of 1/2 * m * v^2 = 8*10^20 J

At the rate of 4418 J / gram of TNT (See TNT equivalent), this generates 1.8 * 10^17 g of TNT = 0.18 teratons (metric) of TNT, give or take 20%. So in order to generate the requisite 1 teraton of TNT-force on impact, a 5-fold increase in the mass, or a 5^(1/3) = 1.7 increase in the radius, is a 17-km bolide. But given the limited precision of these calculations, I left it at one significant figure, or 20-km.

Lifthrasir1 19:40, 19 January 2007 (UTC)

Actually, the mass is 2.6*10^12 tons. Thus, the energy has to be multiplied by 1000,000.--SiriusB 12:06, 22 August 2007 (UTC)

However, there are some other mistakes, so now correctly: 2.6*10^15 kg *0.5*(25000 m/s)^2 = 8*10^23 J or 190 Teratons TNT (1 T TNT equivalent is 4.184*10^9 J). Given the formula in the German WP article we get a magnitude of roughly 11.5 for that impact but 7.1 for Tsar Bomba. But the latter had only about 5 (see Tsar Bomba) which may be due to the atmospheric explosion and the fact that only a small fraction of the air shock (about 1/1000 according to the magnitudes) is transmitted into ground shock.--SiriusB 12:17, 22 August 2007 (UTC)

problem with table

There are two examples of 5.0 with radically different numbers. Which is correct? —The preceding unsigned comment was added by 134.219.128.121 (talk) 12:58, 23 January 2007 (UTC).

Both are correct. The richter scale is actually a measure of ground motion, and there are a number of factors which prevent there being a direct correlation between the amount of ground motion and the amount of energy released. In these cases, there was an equivalent amount of ground movement, but a different amount of energy released. This is due to the fact that the Nagasaki atomic bomb was detonated fairly close to the ground, as it was being used as a weapon, and the Tsar Bomba was detonated quite far from the ground, as it was simply being tested.Upthorn 10:32, 22 April 2007 (UTC)

The base of energy release of the Richter scale is empirical and is over 30

The relationship of the base of the Richter scale to energy release is empirical. Estimates put the base at slightly more than 30. In other words, an increase of two on the scale is over 900 times as much energy release. Although the base is stated several paragraphs into the article, since this is a very significant practical fact, it might be good if it appeared earlier. A lot of the confusion about energy release (see other talk posts) is probably traceable to the article leading off by saying that the base of the scale is 10, and people casually assuming that this is the base of the energy output rather than the amplitude. Brian Hill 07:37, 7 March 2007 (UTC)

The relationship is not quite so simple. The richter scale measures the amount the ground moves, and for this measurement, the logarithmic base is precisely 10, (a 2.0 quake means 10 times as much shaking as a 1.0), however, there are many factors which prevent this from reliably converting into a consistent amount of energy. The most common approximation, however, is that for energy, there is a logarithmic base of 32, starting from 1 pound of TNT at magnitude 0. Upthorn 10:29, 22 April 2007 (UTC)

The explanation for this used to be on the page a while ago, it's as follows:

So, for example, an earthquake of magnitude 5 is ten times greater than one of magnitude 4 and an earthquake of magnitude 8 is 10(8-4) or 10000 times greater than one of magnitude 4.

However, the energy of an earthquake is proportional to the square root of the cube of the amplitude. So each step of the Richter scales has an energy 103/2 (~ 31.6) times that of the previous step. So a magnitude 9 has 10,000 times the amplitude of a magnitude 5, but a million times more energy.

The diminution of amplitude due to distance between the earthquake epicenter and the seismometer is corrected for by subtracting the common logarithm of the expected amplitude of a magnitude 0 event at that distance. This correction for distance is intended to make the local magnitude an absolute measure of earthquake size.

The magnitude of the earthquake, M, is given by:

$M=\log _{10}A+3\log _{10}(8\Delta t-2.92)$

where A is amplitude in millimeters and t is time in seconds.

It's a shame that this explanation was lost to the article, but I guess someone didn't like it. Sekiyu 04:35, 16 August 2007 (UTC)

I hadn't heard the sqrt(1000) explanation before. Richter's original scale was pretty much entirely empirical, with 0 being the smallest detectable (as described in the article under Development). 10 was expected to be the largest imaginable. I learned about the empirical definition after living through Northridge and spending a lot of time in the UCLA physics library during the aftershocks. It is interesting to see statements about the modern and original empirical scales coexisting. Brian Hill 04:46, 21 August 2007 (UTC)

Anyway, based on our discussion here, the importance of the energy released for purposes of damage and comparison with things like explosions, and the widespread confusion on the subject that you see in typical conversation and newspapers, I added a sentence at the beginning of the article making the base 32 point. Hope it works for people. I don't intend this to detract or conflict from the more sophisticated explanations later in the article. Brian Hill 04:48, 21 August 2007 (UTC)

Corrections to table

Removed non-USGS approved adjectives like "massive" and "meteoric" from the table and added supporting references. Ztolstoy 21:51, 9 August 2007 (UTC)

Common misbelief about the Richter Scale

It is commonly believed that a 2 is twice as bad as a 1, that a 4 is twice as bad as a 2, and so on. This is far from correct. I believe it is best to think of the numbers as exponents rather than multiples.

A 2 is a 1 squared.

A 3 is a 1 cubed.

A 4 is a 1 to the fourth or a two squared.

A 5 is a 1 to the fifth.

A 6 is a 1 to the sixth.

A 7 is a 1 to the seventh.

An 8 is a 1 to the eighth or a 3 squared.

A 9 is a 1 to the ninth or a 2 cubed.

A 10 is a 1 to the tenth.

67.188.172.165 19:51, 24 August 2007 (UTC)

So they all equal 1? 128.232.242.178 16:12, 2 October 2007 (UTC)

Yeah... 1^1=1 1^2 or 1X1=1 and so on 2^3 doesn't equal 1^8 2^3=8 1^8=1 Where did you learn math at?

I think it's fairly obvious that when 67.188.172.165 says "a 1" he/she means "the energy released by a magnitude 1 earthquake". Warrickball (talk) 15:28, 12 May 2008 (UTC)

Wrong Scale?

The Indian Ocean earthquake is listed as 9.3 ML in the table however this magnitude relates to the Moment magnitude scale. I believe this earthquake was 8.9 - 9.0 on the Richter scale, but don’t quote me on it. —Preceding unsigned comment added by Allmyfaultsarenormal (talk • contribs) 02:35, 5 September 2007 (UTC)

I'm seconding this. Having clicked on many of the links, notably the 1960 Anchorage earthquake, it appears that the table of magnitudes often lists the moment magnitude scale measurement rather than the Richter magnitude. Warrickball (talk) 15:28, 12 May 2008 (UTC)

According to the Moment magnitude scale page, “The constants in the equation are chosen so that estimates of moment magnitude roughly agree with estimates using other scales, such as the Local Magnitude scale, M_L, commonly called the Richter magnitude scale.”

I believe this means the Moment magnitude scale values are “roughly” interchange with a Richter magnitude scale values. The Moment magnitude scale is also logarithmic as is the Richter magnitude scale. Because the Richter scale has been replaced by an incomprehensible mathematical equation (my opinion), the authors of the equation for good reason still attached familiar values. Therefore it seems quit appropriate to apply Moment magnitude scale values to the Richter magnitude scale.Greg Glover (talk) 02:35, 2 August 2008 (UTC)

Table of Quakes

Exactly. So the table of quakes is wrong and inconsistent. An 9.0 quake is 32 times that of 8.0, not 5.6. And a 8.0 is listed as 20 times that of a 7.0. See TNT equivalent. Also, Indian Ocean Earthquake and Tsar Bomba figures are wrong too on the table and their respective pages. 71.117.93.160 11:08, 2 November 2007 (UTC)

This edit was added after nearly the entire talk page was removed by a vandal. I am replacing it here, as it appears to be useful discussion. Argyriou (talk) 18:33, 14 December 2007 (UTC)

I also see problems in the entries for the Indian Ocean earthquake and Valdivia earthquake. The Indian quake is supposed to be an example of 477 EJ, but it lists an energy of 40 ZJ, which is a hundred times that much. Similarly, the Valdivia quake wrongly compares 747 EJ and 251 ZJ. Pulu (talk) 05:57, 10 March 2009 (UTC)

New Madrid

What about the New Madrid Earthquake... shouldn't that be listed as an example?

Scale Inconsistencies

Logically, 12 in the Richter Scale should be equivalent to 1,000 teratons or a petaton. (If 4 is 1 kiloton, 6 is 1 megaton, 8 is 1 gigaton and 10 is 1 teraton)

Another inconsistency is that the Earth's daily receipt of solar energy is listed as 672 ZJ, while http://en.wikipedia.org/wiki/Orders_of_magnitude_(energy) lists it as being 15 ZJ (A big difference). —Preceding unsigned comment added by 189.25.157.16 (talk) 19:41, 23 April 2008 (UTC)

Well, the solar flux is 1400 Watts per square metre, so multiplying that by the cross-section area of the Earth, which is pi times 6378000^2, gives the power intercepted as 1.8E17 Watts. In 24 hours it is 1.5E22 Joules. A Zetta-Joule (ZJ) is 10^21 J so the energy intercepted per day is 150 ZJ. That can be compared with the human use of energy which is 1.4E18 Joules per day, equal to 1/10000th of the energy arriving from the sun. 82.34.45.137 (talk) 16:49, 15 March 2011 (UTC)

Development POV

The Development section says that this was developed by Richter in partnership with Gutenberg, yet the POV seems to infer that Richter was the only person involved. "His inspiration was..." , "His motiviation...". It speaks nothing of Gutenberg's contributions to the development. Can anyone who is knowledgeable on the development comment?Bgautrea (talk) 16:31, 12 May 2008 (UTC)

Gutenberg's contribution may or may not be be significant. In any case, the article as it is currently written states: "Many scientists and historians feel it should be known as the Richter–Gutenberg scale, and Richter himself never attached his name to it, calling it the 'earthquake magnitude scale' ". That a scientist does not use his own name for his or her creation is a poor argument, because many would regard it merely as arrogance to name something for oneself. 130.153.28.208 (talk) 08:48, 16 June 2008 (UTC)

Inconsistant information in article?

In the article section "Development" there appears the statement "Because of the limitations of the Wood-Anderson torsion seismometer used to develop the scale, the original ML cannot be calculated for events larger than about 6.8." Surely if this is the case then no quakes should appear in the tables above this magnitude, unless I am misunderstanding what the text means. Can anyone clarify this for me?

Doc John —Preceding unsigned comment added by 72.214.244.130 (talk) 22:35, 14 May 2008 (UTC)

accuracy issues

I'm not quite sure that it's practical to calculate the energy yield of earthquakes. The duration of an earthquake is also a major factor. For example, I'm pretty sure that a 10-minute 7.8 earthquake would release more energy than a two-second 8.2 earthquake. --Ixfd64 (talk) 19:38, 16 May 2008 (UTC)

Correctly revised the scale

Hay there folks, I’ve read all the postings. I can’t vouch for the examples (lower table) but the Approximate TNT for seismic energy yield is mostly correct. The Richter scale energy levels are based in the total energy release of 1 gram of TNT. Since energy is mutually convertible TNT was used as the tangible foundation for the total release of energy.

The scale itself is logarithmic. Therefore each whole number on the scale is approximately 31.62 times greater than the next. That is, a 4 on the Richter scale is 31.62 times greater than a 3 on the Richter scale. A 5 on the Richter scale is 31.62 times greater than a 4 on the Richter scale. Since 31.62 squared equals a 1000, all the odd whole numbers on the Richter scale are 1’s in total energy release. Conversely all the even whole numbers on the Richter scale are 31.6 in total energy release. Also, the same is true for fractions thereof. A 5.3 on the Richter scale is 31.62 times greater than a 4.3 on the Richter scale.

I’m not too good with logarithms (I am now), so I had to graph the 10th (.1, .2, .3, .4, .6,.7,.8 and .9). The 8th are easy because they are all square roots of square roots (.125, .25, .375 etc...).

Because the "Richter magnitudes examples" has been so corrupted I did the Log₁₀ to correct the table and set it correct for 1. Greg Glover (talk) 00:40, 15 March 2011 (UTC)Greg Glover (talk) 06:03, 18 March 2011 (UTC)

So here are the correct logarithmic numbers for 0 to 1.0 to 3.0 on the Richter scale. The scale repeats itself from 3.0 to 5.0, 5.0 to 7.0, 7.0 to 9.0 and so on. Also the scale itself, irrespective of the equipment measuring the seismic event can have negative values (those below 0.0) and values over 10. Greg Glover (talk) 15:04, 31 July 2008 (UTC) Greg Glover (talk) 00:40, 15 March 2011 (UTC)Greg Glover (talk) 06:03, 18 March 2011 (UTC)

This set (table) of numbers should help with the accuracy issue as stated above; they are exact as rounded to the nearest tenth.

Richter Approximate Magnitude	Approximate TNT for Seismic Energy Yield	Joule equivalent	Example
1.0	1.0 kg	4.2 MJ
1.1	3.1 kg	13.0 MJ
1.2	5.4 kg	22.6 MJ
1.3	4.9 kg	33.1 MJ
1.4	10.7 kg	44.8 MJ
1.5	13.8 kg	57.7 MJ
1.6	17.0 kg	71.1 MJ
1.7	20.4 kg	85.4 MJ
1.8	23.9 kg	100.0 MJ
1.9	27.6 kg	115.5 MJ
2.0	31.6 kg	132.2 MJ
2.1	97.3 kg	407.1 MJ
2.2	169.1 kg	707.5 MJ
2.3	251.0 kg	1.1 GJ
2.4	339.7 kg	1.4 GJ
2.5	435.3 kg	1.8 GJ
2.6	537.2 kg	2.2 GJ
2.7	644.5 kg	2.7 GJ
2.8	756.5 kg	3.2 GJ
2.9	874.0 kg	3.4 GJ
3.0	1 megatonne	4.2 GJ

Greg Glover (talk) 04:08, 31 July 2008 (UTC)

Corrected for all parameters. Greg Glover (talk) 08:39, 18 March 2011 (UTC)

Hello, I am concerned that the table mentioned above is incorrect The USGS website http://earthquake.usgs.gov/learning/faq.php?categoryID=2&faqID=33 provides a comparison (in joules) for Richter Magnitudes over 4. From this chart M7 is 31 times greater than M6 and 1000 greater than M5 as expected but these DO NOT agree with the table provided on the main page. Given the degree of discrepancy I think it best to remove the table temporarily. —Preceding unsigned comment added by 211.30.105.28 (talk) 03:34, 5 November 2008 (UTC)

Additionally,

A rough estimation is given by Gutenberg cited in Gere and Shah (1984, p.79) "Terra Non Firma: Understanding and Preparing for Earthquakes" for the amount of seismic energy released (E, in ergs) based on the Richter magnitude (M):

Log E = 9.9 + 1.9M – 0.24M ²

This, when converted to joules corresponds to the values given by USGS (above) and not to the chart shown in the article.

This scale has nothing to do with the USGS. The Richter scale readings are not proportionate or scalable to the Moment magnitude scale.

Greg Glover (talk) 08:52, 18 March 2011 (UTC)

Well, I can't do log's (I can now 01 MAR 11) or calculus but I can add and subtract. So if the USGS can't make up it's mind I say leave the table alone. To prove my argument click on the link you have provided above. Read the caption then look at the table for Joules converted from Me and Ms or Mw. You will see that Ms or Mw converted Joules are 3 times the energy of the Me converted Joules. Sorry I don't care how you do the math, one Joule equals one Joule. Unless of course you have misunderstood that there are several ways to interpret the energy release predicated in the magnitude scale used; M_s, m_b m_o. Also the tones of TNT equivalent are 15 times greater than the wiki table. Please read the wiki article on TNT equivalent and you will see that the Richter Scale equivalent table corresponds exactly with the TNT equivalent table. I think the wiki table is very correct. If you want to use a different magnitude scale (and create a differant table) in another place within Wikipedia, then by all means, go for it.Greg Glover (talk) 05:14, 6 December 2008 (UTC)

Scale and Table corrected for all parameters. See 34, “Add a new constant unit column to the magnitude table, xref to tsunami?” for details on parameters. Greg Glover (talk) 00:40, 15 March 2011 (UTC)

why is this (semi) protected?

I'm well out of date, but isn't it normal to explain on the discussion page why an article is semi-protected? —Preceding unsigned comment added by 81.6.250.44 (talk) 08:51, 14 October 2008 (UTC)

It was semi-protected on 25 September 2008 by Graham87, and that action seems to have been in response to some weird non-signed-in vandal who was just deleting great chunks (but not all) of this page. Bizarre (or an odd proxy war; I don't really care). However, given how long ago it was now and the fact that the admins concerned do not seem to be keeping a close eye on this page, I doubt that we'll be able to get much more information on what was going on than that. –Donal Fellows (talk) 21:15, 28 December 2009 (UTC)

Example

Isn't using other Earthquakes to describe the energy released at certain Richter's kind of defeating the object? It's like defining a word and reusing the word in the definition. Aren't there other possible examples to use (like the others have, with bombs)? Adz657 (talk) 21:51, 1 November 2008 (UTC)

I think the intent of the original author was to give a comparison for folks that live in different geographical places. I live in Los Angeles, California, USA. By seeing the earthquakes in different parts of the world I get an idea of what those folks may have experienced. Defining earthquakes by earthquakes is fine by me.Greg Glover (talk) 05:20, 6 December 2008 (UTC)

missed an earthquake —Preceding unsigned comment added by 69.208.125.9 (talk) 03:48, 17 February 2009 (UTC) Hello on the earthquake scale you didnt enter the 7.3 earthquake in the Iranian city of Manjil.

Evolution?

What evidence do we have that the Toba eruption impeded on the theory of Human evolution? This line should have evidence to back it up- or be deleted. Evolution in of itself is a very contervisail theory both in and outside the scientific world. I don't see why we should make a innocent enough topic about somthing so controversial.

"Toba eruption 75,000 years ago; which, according to the Toba catastrophe theory, affected modern human evolution" —Preceding unsigned comment added by 75.179.163.66 (talk) 06:05, 3 April 2009 (UTC)

That item can probably be replaced with wording like "Toba eruption 75,000 years ago; largest known volcanic eruption" though I'm not sure where the figure for the energy released came from. For one thing, we don't know what earthquakes accompanied the eruption. At the very least, a citation should be present c(couldn't find anything relevant-looking on the linked page). –Donal Fellows (talk) 21:31, 28 December 2009 (UTC)

The Toba ctastrophe theory may be controversial in its effect on human evolution, but evolution of life on Earth is one of the most fact-supported theories in science, and the only "controversy" surrounding it has been invented by fundamental religious groups. Evolution is the basis of all modern biological and medical research; it is as factual as any 'theory' in science, i.e. Theory of Gravity, Heliocentric Theory, Atomic Theory. Cruxster (talk) 23:21, 14 March 2011 (UTC)

Local view in effects table?

I think that presenting a U.S. Geological Survey document is a local view. The effects of an earthquake heavily depend on how the buildings were built and in the U.S. the only major seismic regions are either supersafe (California) or very sparsely inhabited (Yellowstone). This may be different in other regions, where you can have casualties even for 5.5-scale earthquakes such as in Lincolnshire. Balabiot (talk) 15:55, 6 April 2009 (UTC)

Effects of Magnitude 13

According to a video on this web page: "Life After People" Videos (Discovery Channel), a magnitude 13 earthquake would cause volcanoes. If people think this is worth mentioning, perhaps it could be added to this page, with an appropriate reference? Radical Mallard April 17, 2009, 6:47 PM EST

Its actually a meteorite that causes the earthquakes and erupting volcanoes in the video. An earthquake larger than magnitude 10 is impossible under normal circumstances, so I say let that be the largest figure for now. RapidR (talk) 23:29, 17 April 2009 (UTC)

Link to yucatan impact?

Shouldn't there be a redirect or something of sorts to the "Cretaceous–Tertiary extinction event"? —Preceding unsigned comment added by 75.36.162.102 (talk) 13:21, 22 July 2009 (UTC)

This reference should be removed completely. There is no evidence to support giving the impact a rating of 13, nor the date given. This is a non-controversial topic, why add controversy? —Preceding unsigned comment added by 205.229.151.150 (talk) 22:05, 13 January 2010 (UTC)

Missing scales in Table?

Is there such a thing as an earthquake of scale 2.95 (or 3.95, or 4.95,...)? These magitudes are missing from the first table in the article. One magnitude ends at .9 and the next starts at .0. —Preceding unsigned comment added by 129.27.152.126 (talk) 08:43, 5 October 2009 (UTC)

Earthquake magnitudes are normally only quoted to the nearest 0.1, so that explains the table. Theoretically you could quote the magnitude to greater precision, but that would imply greater certainty than is normally available. When different organisations estimate magnitudes for the same event, they almost never agree exactly, because they use different techniques, different observations etc. Essentially the precision used reflects the uncertainty in the estimated magnitude. Mikenorton (talk) 09:49, 5 October 2009 (UTC)

Energy Equivalents Table Incorrect?

Forgive me if I'm wrong, but isn't it impossible to have an earthquake that measures over 10.0 on the Richter scale? Perhaps if you were comparing things in the other direction it would make more sense (like saying such-and-such blast is equal to 2 Hiroshimas; you wouldn't say "if Hiroshima was twice as large, it would be equal to 1 such-and-such blast), although even then I would wonder why earthquakes are being used rather than something more easily conceived like "X Tons of TNT" If there's a good reason though, I'd love to hear it... ZbeeblebroxIV (talk) 08:49, 2 December 2009 (UTC)

Toba Eruption Citation

I added a {{fact}} request to the text referring to the Toba eruption (in the table of examples of events of particular magnitudes) because it would be really nice to have a citation for the amount of energy released in the eruption (the info should go in the linked page too). I couldn't find such information at the linked page, which is full of information about other effects. Note that a citation for the existence of the eruption would be not in itself suitable! If we can't get something for the energy, it should go from the table; after all, there's plenty of other examples to go round, especially at that magnitude, so dropping one from the table would not be a huge loss. –Donal Fellows (talk)

Haiti Earthquake Example

The Earthquake in Haiti is said to be 7.0 on the Moment magnitude scale, but it doesn't say it's the same value on the Richter Scale, is this value correct? Private meta (talk) 14:29, 15 January 2010 (UTC)

Most of the values for larger earthquakes quoted in the table as examples are actually moment magnitudes. I don't understand why we use earthquakes over 6.9 (at which the article says the scale tends to saturate) in the table, we certainly don't need more than one for each value. The point of the table (I'd be happy to see it go personally) is getting lost and it's turning into a list of earthquakes by magnitude (M_w). Mikenorton (talk) 12:32, 29 January 2010 (UTC)

Yes I think removing the energy table, or at least simplifying it, would be a good idea as it will just get longer over time. It is incorrect anyway as indeed the article is about the ML scale, in which the upper limit of calculation is about 6.8 or so yet the values on the table go up to 13. The whole magnitude thing is complicated, mainly because the media still use the term "on the Richter scale", people naturally see it as the earthquake magnitude scale, which is technically not correct. RapidR (talk) 18:00, 29 January 2010 (UTC)

I agree to that. The energy table just adds to the confusion. nihil (talk) 23:40, 27 February 2010 (UTC)

Diagram

Would it be possible to make a (foolproof) diagram of the escalating force of the earthquake in richter scale? --85.197.210.44 (talk) 14:35, 27 February 2010 (UTC)

"Effective"

Maybe it's just me (it wouldn't surprise me a bit) but I don't know what this means "The effective limit of measurement for local magnitude ML is about 6.8." This is near the top of the article. Why is the effective limit of measurement around 6.8? What is meant by "effective" in the example given? —Preceding unsigned comment added by 75.48.2.10 (talk) 20:05, 2 March 2010 (UTC)

You're right, it's not that clear. The richter magnitude becomes less effective at discriminating between earthquakes of different energy output above about 6.8. This is why the moment magnitude scale was brought in to allow better comparison between larger quakes. It's often said that the richter scale tends to 'saturate' at 6.9 and above, which means that the richter magnitude tends to underestimate the energy release. The moment magnitude scale article explains all this fairly well and I'll try to add a bit to this article to make it clearer. Mikenorton (talk) 20:40, 2 March 2010 (UTC)

Edit request

{{editsemiprotected}} Please change:
Richter arbitrarily chose a magnitude 0 event to be an earthquake that would show a maximum combined horizontal displacement of 1 µm (0.00001in) on a seismograph recorded using a Wood-Anderson torsion seismometer 100 km (62 mi) from the earthquake epicenter.
to:
Richter arbitrarily chose a magnitude 0 event to be an earthquake that would show a maximum combined horizontal displacement of 1 µm (0.00004in) on a seismograph recorded using a Wood-Anderson torsion seismometer 100 km (62 mi) from the earthquake epicenter.
because 1µm is about 0.00004 in (http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&q=1e-6+m+in+in&aq=f&aqi=h1&aql=&oq=)

done. Josh Parris 13:28, 5 March 2010 (UTC)

Logarithm is not a homogeneous function

Logarithm is not a homogeneous function. Therefore it dos not make sense to write a logarithm of a dimensional quantity. The formula of M should reed: M=log(A/A0) . The reader would appreciate to have a concrete notion of the meaning of A0. So if the epicentral distance of the station is zero the reader would like to know if an earth quake of magnitude zero corresponds to an amplitude of 1 inch, 1 micrometer, 1 millimeter, 1 meter or whatever. 200.131.19.54 (talk) 12:44, 21 April 2010 (UTC)

Pending changes

This article is one of a small number (about 100) selected for the first week of the trial of the Wikipedia:Pending Changes system on the English language Wikipedia. All the articles listed at Wikipedia:Pending changes/Queue are being considered for level 1 pending changes protection.

The following request appears on that page:

However with only a few hours to go, comments have only been made on two of the pages.

Please update the page as appropriate.

Note that I am not involved in this project any more than any other editor, just posting these notes since it is quite a big change, potentially.

Regards, Rich Farmbrough, 20:23, 15 June 2010 (UTC).

About the definition for "10+" Richter scale level

I don't believe "Epic" is used correctly in this context. No citation can be provided because no mention of this term used to describe the Richter scale exists in scientific literature. It should be changed to "enormous", "extraordinary", or "extreme", which are the terms used more conventionally. The tenth level of the scale is rarely included to start with, since there is no record of a natural geological phenomenon reaching such intensity. — Preceding unsigned comment added by Ayreos (talk • contribs) 23:09, 11 March 2011 (UTC)

Add a new constant unit column to the magnitude table, xref to tsunami?

i. For the reader looking at this page after a newsworthy event, the inclusion of a constant unit column (e.g. MJ) would display the +2==1000x relationship more clearly. I know the info is in the text (para 3), but perhaps some casual readers such as myself skip over the tech reading and go straight to the table. Perhaps a whole new table? Just a thought...

Richter 
Approximate 
Magnitude    __ MegaJoules (MJ) __
0	                      0.06
1		              2.00
2	                     63.10
3			  2,000.00
4			 63,100.00
5		      2,000,000.00
6		     62,700,000.00
7		  2,000,000,000.00
8		 63,100,000,000.00
9	      2,000,000,000,000.00
10	     63,100,000,000,000.00

ii. Should a cross-reference to tsunami be added?
10:13, 12 March 2011 (UTC) —Preceding unsigned comment added by 72.138.3.250 (talk)

Hay fix your table. 6 on the scale should read 63,100,000.00 not 62,700,000.00. :) Greg Glover (talk) 02:09, 15 March 2011 (UTC)

Again, I see there is a disagreement as to what Charles Richter and Beno Gutenberg based their scale on; the pound or kilogram. You propose that the scale is based on the pound; giving the 2.00 for a 1 reading on the Richter Scale. Actual 1 lb equals 453.6 g, which equals 1.89 MJ of released energy. So, 1.89 MJ rounds-up nice and tidy to 2.0 MJ. Or did you make the mistake of Log (1000; 31.62) is equal to 2?

I, on the other hand, have read that the standard was 1 gram of TNT. However, the gram was too small a release of energy so 1 kilogram was established as 1 on the scale. This is also why you can have negative values and values of greater than 10. Remember that the Richter scale is an extrapolation of values based on the readings from the equipment used for measuring the quake.

I prefer to use the correct starting point. I believe that is the kilogram. If so see above for the corrected scale. Also if others believe 1 pound is the correct starting point that's okay too. But the currant table over on the “Article Page” is incorrect. It is set to a Parabola or a Catenary to be specific. The actual curve (a Dogleg) is a Log₁₀. If the community wishes to use 2.00 MJ as 1.0 on Richter scale, then I will reconfigure the tables on both the “Discussion Page” and “Article Page” to reflect this. Greg Glover (talk) 01:21, 15 March 2011 (UTC)

Article is incorrectly mixing Richter magnitude values with moment magnitude values

Richter magnitude scale is subject to saturation in the high-magnitude range, and it's maximum value for earthquakes on Earth is below 9. The table at Richter magnitude scale#Richter magnitudes examples claims several earthquakes have had higher Richter magnitudes, but the sources are talking about magnitudes on Moment magnitude scale. All earthquake energy values are incorrect too, because the source [1] is talking about moment magnitude scale and this article is talking about Richter scale. I will remove all major earthquakes which seem incorrect and I think they should not be added back unless there are reliable sources for the values. 82.130.23.80 (talk) 19:42, 14 March 2011 (UTC)

We had this discussion. Read above at 16, “Correctly revised the scale”. I would request you first check with the community before making that large a change to the article. Greg Glover (talk) 01:27, 15 March 2011 (UTC)

However, 82.130.23.80 (talk) 19:42, 14 March 2011 (UTC), I understand what you are conveying. The hardest of the earth's crust is Basalt That is, the Oceanic crust versus the Continental crust. The oceanic crust is equal to 3.3 g/cm³ and the continental crust which is made up of mostly aluminum silicate is 2.7 g/cm³.

The energy to break basalt (again harder than aluminum silicate) was originally to be 10 on Richter scale or the maximum amount of energy it took to break the earth's crust. But due to the uses of 1 gram as the standard for 1.0 on the Richter, the scale was set back. Remember, if 1 g equals 1.0 on the Richter scale then 32.6 g would equal 2.0 and 10.0 on the Richter scale would be the saturation point and that mathematically does not work.. Therefore, the scale was set back to equaled 1.0 as 1 kg as the starting point and 9.0 on the Richter to scale equaled the saturation point. Arguably, on the number line 8.5 should be the saturation point, but actually due to the set back point the saturation point is 8.6 . When rounded-up it is said to be 9.0

That my friend is what you are pointing out!

Ultimately the scale is just a conversion table that is based on the energy released by 1 g of TNT. When the scale was compressed to equal the energy released of 1 kg or 1.0 on the Richter scale it pushed the value of 1 g back to .01 kJ or negative 1.0 kJ.

In short the scale is a conversion table and is infinite, not finite. It is the recording equipment (Wood–Anderson torsion seismometer) that is finite. Don't confuse the two. Greg Glover (talk) 05:33, 15 March 2011 (UTC)

Richter magnitudes based on 2.0 MJ

Here is the correct table for Richter scale equivalents done by Log₁₀. Even though all the numbers are exact, the original base number of 2 megajoules is an approximation. Therefore all values are an approximation. Greg Glover (talk) 11:00, 18 March 2011 (UTC)Greg Glover (talk) 11:23, 18 March 2011 (UTC)

In my never-to-be- humble opinion, the base number 2 is way off. Well actually the base number is off by 2.1 times or the approximate difference between the kilogram and pound;2.204623.Greg Glover (talk) 00:50, 16 March 2011 (UTC)

Richter Approximate Magnitude	Approximate TNT for Seismic Energy Yield	Joule equivalent	Example
1.0	476.0 g	2.0 MJ
1.1	1.5 kg	6.2 MJ
1.2	2.5 kg	10.6 MJ
1.3	3.8 kg	15.8 MJ
1.4	5.1 kg	21.4 MJ
1.5	6.6 kg	27.6 MJ
1.6	8.1 kg	34.0 MJ
1.7	9.7 kg	40.6 MJ
1.8	11.4 kg	47.8 MJ
1.9	13.1 kg	55.2 MJ
2.0	15.0 kg	63.1 MJ
2.1	46.2 kg	194.0 MJ
2.2	80.3 kg	337.2 MJ
2.3	118.9 kg	499.2 MJ
2.4	161.1 kg	676.8 MJ
2.5	206.5 kg	867.2 MJ
2.6	261.9 kg	1.1 GJ
2.7	309.5 kg	1.3 GJ
2.8	357.1 kg	1.5 GJ
2.9	404.8 kg	1.7 GJ
3.0	476.0 kg	2.0 GJ

An example of this table and the table that appears on the “Article Page” as been incorrect is the entries for the 12.5 quake; “Yucatán Peninsula impact (creating Chicxulub crater) 65 Ma ago (10⁸ megatons; over 4x10³⁰ ergs = 400 ZJ)”and the 23.0 quake; “Approximate magnitude of the starquake on the magnetar SGR 1806-20, registered on December 27, 2004.”

The 12.5 quake is 100 teratonnes and 400ZJ or exactly a 12.22 quake at 95.6 teratonnes and 400 ZJ of energy displaced and the 23.0 quake is 4.2×10²⁹ tonnes and 1.3×10³⁹ J or exactly a 22.44 quake at 3.1×10²⁹ tonnes and 1.3×10³⁹ J of energy displaced.

So after correcting both the 12.5 and 23.0 quake for magnitude and equivalents based on 1 kilogram of TNT, both entries are ostensible correct. I would hope that the community would reconsider using 2 megajoules as its base and go back to the correct 1 kilogram of TNT base. Even the headings on the table support my contention; “Approximate TNT for Seismic Energy Yield” and “Joule equivalent” Again the tabe is based on the energy release of TNT not the Joule.Greg Glover (talk) 01:51, 16 March 2011 (UTC)

Could you please share which reliable source you plan on citing for this data because right now it looks like original research. —Elipongo (Talk contribs) 18:12, 18 March 2011 (UTC)

My first source is Logarithmic scale. My second source is Base-10. My third source is Richter magnitude scale, third paragraph. My forth source is Add a new constant unit column to the magnitude table, xref to tsunami?, My fifth source is Richter magnitudes examples Table its self and finally: 2.0, 6.2, 10.6, 15.8, 21.4, 27.6, 34.0, 40.6, 47.8, 55.2, 63.1, 194.0, 337.2, 499.2, 676.8, 867.2, 1.1, 1.3, 1.5, 1.7, 2.0. Or in words, LOG₁₀ ,based on 2.00 megajoules per Add a new constant unit column to the magnitude table, xref to tsunami?. Example: 31.55 to the power of 0 equals 1 times 2 equals 2 or the base 2 MJ.

So my source is Wikipedia.

Are you prepared to call into question the content of Wikipedia?

Greg Glover (talk) 02:34, 19 March 2011 (UTC)

Most certainly. Wikipedia is not a reliable source. Even if it was, we can't couldn't cite ourselves to justify ourselves. —Elipongo (Talk contribs) 16:09, 20 March 2011 (UTC)

Japan earthquake, 2011

Someone wrote this note within the 9.0 quake measurement. “Even though this was measured in the Moment Magnitude Scale, it should be included as was the Christ Church quake, otherwise all newer quakes should be removed. This might not be a bad idea. Should a note be made that all new earthquakes are measured in the more accurate (especially for 6+ quakes) Moment Magnitude Scale and a reference to Largest_earthquakes for people who come here to see quakes and their strengths. Most people think that the Richter Scale is the only scale.”

Although I do not agree with the removal of all the newer quakes because they are measured on the Moment Magnitude Scale, I would agree to add a “reference” to all new quakes. I support the re-addition of the Japan earthquake, 2011 quake to the Table.Greg Glover (talk) 16:44, 17 March 2011 (UTC)

If they're to be listed the quakes measured on Moment Magnitude Scale should be converted to the Richter Scale, otherwise listing them here makes no sense. —Elipongo (Talk contribs) 02:56, 18 March 2011 (UTC)

Yes, listing every major quake (5.0 or above) here makes sense. Tens of millions of people,every year, come here to Wikipedia to read what the Richter scale reading is. There are only a few score (I am assuming) of you people that are pure to the Moment magnitude scale that feel the reported scale readings “makes no sense”.Greg Glover (talk) 09:07, 18 March 2011 (UTC)

Friend, I didn't say not to list them. I said that if they're listed their magnitudes need to be converted to Richter scale values. The title of the table is "Richter magnitudes examples", mixing in listings measured in another scale would be misinforming people who come here to learn about these things. People who didn't know that the Richter scale has been superceded should come away from this article with that new knowledge- that is the business we're in here, right? A cross-reference to the more inclusive Largest earthquakes by magnitude is already listed at the introduction of the table, so people wanting to compare earthquakes can go there. I will say again that I have no objection to more recent quakes being listed here, so long as their magnitudes are converted to the Richter scale so that we're not mixing apples & oranges and misinforming our readers thereby. —Elipongo (Talk contribs) 10:24, 18 March 2011 (UTC)

I understand Elipongo and you are absolutely correct. Also, to address ( Mikenorton ) the thoughts below, I just picked 5.0 thinking it was major. I didn't realize there are thousands per year. I agree lets just post the “major quakes” and convert them to Richter magnitude scale ($M_{L}$)from, Moment magnitude scale (M_W)

Unfortunately my math prevents me from being able to the conversion from M_W to $M_{L}$. However, I can do the Log₁₀ for 2 MJ base Richter magnitude scale from zero to infinity.

I am in the process of correcting the Tables on the “Article Page and “Discussion Page” for Log₁₀ including the diminishing return it yields.

Greg Glover (talk) 19:16, 18 March 2011 (UTC)

I presume that there is no serious suggestion to list "every major quake (5.0 or above)" here, there would be thousands of them. Far better in my view that, if we must have comparisons, restrict it to just one 'well known' earthquake for each magnitude, or this list will take over the article. Mikenorton (talk) 12:51, 18 March 2011 (UTC)

I don't know how to do such a conversion either, Greg. My suspicion is that nobody has done such a conversion for the same reason that the Moment Magnitude Scale was invented; the Richter Scale saturates at higher magnitudes and all the larger events would cluster around similar values. As for your correction of the values in the tables and your assertion that the scale is infinite in scope, can you please cite your sources because right now it looks a lot like original research. —Elipongo (Talk contribs) 19:35, 18 March 2011 (UTC)

Yes! And I'm not trying to be arrogant, presumptuous or flip. My first source is Logarithmic scale. My second source is Base-10. My third source is Richter magnitude scale, third paragraph. My forth source is Add a new constant unit column to the magnitude table, xref to tsunami?, my fifth source is Richter magnitudes examples Table its self and finally: 1,2,3,4,5,6,7,8,9,10,20,30,40,50,60,70,80,90,100,200,300,400,500,600,700,800,900,1000. Or in words, simple math; LOG₁₀: which is not “Original research”.

I guess what I'm trying to say, is that I want to go back to 31 July 2008. I'm not promoting my own “original research”, I'm promoting what was here on or before 31 July 2008.

Greg Glover (talk) 21:29, 18 March 2011 (UTC)

• I would hope the Wiki community here at Richter magnitude scale has finally decided to keep the Richter magnitudes examples Table and just up date it for Major Quakes (converted of course).

In other words, this Wiki Community has finally end the discussion as to keeping or discarding the Richter magnitudes examples; we are keeping the Richter magnitudes examples Table .

Would you Gentlemen and any Ladys out there please support me in keeping and properly up dating the Richter magnitudes examples Table? Thanks for your support and input!!!

Greg Glover (talk) 19:38, 18 March 2011 (UTC)

 Yes I agree with Greg Glover and will do my best to keep the table up-to-date with current earthquake events. Xionbox^₪ 21:29, 18 March 2011 (UTC)

Thanks for explaining how you arrived at your conclusions. The article's third paragraph is referenced to this page at the USGS website. Reading it puts light on the situation. The Richter Scale measures a particular kind of ground movement. This ground movement correlates to the energy released by a quake, but only up to a point. This inherent limitation is what forced seismologists to invent the more versatile Moment Magnitude Scale. The tables you have made conflate the Richter scale's ground movement measure with the energy released by a quake. While the two do correlate over a range, they are fundamentally different things. Attempting to use the limited correlation to extend the Richter Scale over a wider range than listed in reliable sources constitutes Synthesis and thus is original research per our policies. —Elipongo (Talk contribs) 23:22, 18 March 2011 (UTC)

I disagree. You are arbitrarily applying the limits of $M_{W}$ scale to a limitless $M_{L}$ scale. As you can read and I cited the Richter scale ( $M_{L}$ ) is infinite [see the 12.33 and 22.78 quake entries: they are sourced and read the above post]. I did not post the 12.33 quake or the 22.78 quake. These two posts are proof of my contention that the Richter scale is infinite.

Elipongo, please cite your sources, because right now it looks a lot like your assertion that the Richter magnitude scale is finite, is original research.

I enjoy and encourage this form of discord. It appears at this point I have impeached your assertions. Please challenge me with other sources. I will gratefully and humbly meet your claims!!!

User:Greg Glover|Greg Glover]] (talk) 00:15, 19 March 2011 (UTC)

The scale itself is has no upper bound, but is practically limited by the response of a Wood-Anderson torsion seismometer to larger earthquakes. The same is also true for both the body-wave and surface-wave scales Ms and Mb in that all three scales tend to "saturate" at magnitudes above about 7, which is why the MMS has been used for most larger earthquakes. It is trivial to calculate released energies equivalent to Mw scale magnitudes by using Kanamori's equations e.g. Mw 9.0 gives 1.77 PJ, so such energies can be calculated but I'm not sure about converting them back to Richter magnitudes. When Kanamori came up with the MMS his aim was to make it consistent with the Richter Scale up to about 7.5 - I don't personally see a problem with using Mw values, as long as these are clearly shown in the table with some sort of comment. Mikenorton (talk) 08:16, 19 March 2011 (UTC)

But what is the point of listing M_w values in a table entitled "Richter magnitudes examples"? It seems to me that we would only be confusing the readers whom we should be informing that this scale has been superseded. We already have several lists of earthquakes for people wanting to see more complete earthquake listings. And Greg, I did cite a reference, right there in the second sentence of my post you replied to. —Elipongo (Talk contribs) 16:06, 20 March 2011 (UTC)

I guess what you fail to understand, is there no difference between a 9.0 on the $M_{W}$ scale and a 9.0 on the $M_{L}$ scale ; as it pertains to the Table, not the article. That is why this table is given in the approximate TNT release and Joules equivalent.

The people of the world can not comprehend, a Million Million Joules release of energy 8 kilometers (5 miles) underground. That’s why examples of bombs, hand grenades and thermo nuclear devises are also added in. We understand the the horrible deviation TNT and atomic bomb bring about. It helps us understand how bad the Japan 2011 Quake really was.

If you have never gone through a 3.0 or 6.0 on the scale. You will never know how many more thousands of times, more scary, a 6.0 is then a 3.0. That is why the scale should remain.

All that is necessary, is to put this Disclaimer in front of any new quake:

• Sendai earthquake and tsunami (Japan), 2011

• This quake was measured using the more accurate Moment magnitude scale $M_{W}$. Please be advised that the magnitude “number” (example 6.0) displayed at the front of this Table, for this quake, may represent a significantly greater or lesser release of energy.

Or something along those lines.

Also as of proof that I understand that current scale is wrong, is this: 63.1 kJ squared is 3918.51 kJ (3.9 MJ); not 2000 kJ ( the 2 MJ Base). Therefore the current scale can not be right. But I don't care. If you want to use 63.1; fine that's okay. theree is only 2.1 times the difference between 31.623 (31.55) and 63.1. What matters is the the scale convey to the world that a 2.0 on the scale is 31.6 times greater than a 1.0 on the scale. And that a 3.0 on the scale is 1000 times greater than a 1.0 on the scale.

Greg Glover (talk) 02:17, 21 March 2011 (UTC)

Sir, you miss my point entirely. Let me see if I can better illustrate it by changing the names involved. Let us say there was a "list of famous dogs", we could include Rin-tin-tin, Lassie, Checkers, Snoopy, etc. Now let's say an editor wanted to add Felix, Socks, and Garfield because they're famous too and people should see them all. People might point out that not only are cats not dogs, but including them duplicates the existing "list of famous animals". Now here we have a List of Richter Magnitude Examples and you're wanting to add listings of Moment Magnitude examples which are patently not the same thing. We already have Lists of earthquakes that this would be duplicating. All listings here should be in the Richter scale and no other, your assertion that the Richter scale can be extended by using energy equivalence is in contradiction to the references cited in the article. Now it is entirely possible that I am completely off-base, so I'm going to post a note at Wikipedia talk:WikiProject Earthquakes requesting participation in this debate. —Elipongo (Talk contribs) 05:24, 23 March 2011 (UTC)

Richter magnitudes examples Table

I have brought back the old Table. It still uses the 2 megajoules base. All the old major quakes appear and I have started denoting them for their correct magnitude scale: $M_{W}$ or $M_{S}$. If it was $M_{L}$ then I put nothing as this is the $M_{L}$ page.

I had to move a couple of examples, but it was done in conformity with Wikipedia. That is, Wikipedia was the source for the information, not me.

I hope the community is okay with this compromise and there will be no edit waring of this Table.

Yes, the Table will get longer but that’s okay. There is plenty of room on the page for the next 100 years.

Greg Glover (talk) 18:05, 21 March 2011 (UTC)

Can somebody include this one? http://en.wikipedia.org/wiki/1911_Kebin_earthquake I'm pretty sure I'll break something if I do it myself. The earthquake's well known in Russia and Kazakhstan, mainly due to stories about http://en.wikipedia.org/wiki/Ascension_Cathedral,_Almaty with its window glasses staying intact —Preceding unsigned comment added by 217.29.95.125 (talk) 05:33, 8 April 2011 (UTC)

No problem with the 2.0 MJ (correctly, 478 g of TNT, based on 4.184 kJ/g) base for magnitude 1.0; however, much of the rest of the table is inconsistent with this. A 0.1 change in magnitude should correspond with a factor of 1000^0.05 ≈ 1.41254. If nobody else fixes the in the next 12 hours, I'll do so myself, Internet access permitting. 8-) — Glenn L (talk) 15:06, 29 April 2011 (UTC)

No takers? Okay, I've done it myself with just two significant digits. —— Glenn L (talk) 05:03, 30 April 2011 (UTC)

Chernobyl nuclear disaster

I don't have any quarrel with the overall change because I don't have the requisite knowledge to do so. But the reference to the 3.74 as being attributable to the "Chernobyl nuclear disaster" is inaccurate (and something on which I do have plenty of knowledge). The disaster itself was related to the release of radioactivity as a result of numerous causes. One of the causes was a major explosion at the plant; that is the 40 GJ impact experienced. None of the other outcomes or impacts of the overall disaster was relevant. Just a friendly correction from your local nuclear engineer/accident risk assessment professional... Ψν^Psi_nu 05:15, 22 March 2011 (UTC)

I'm not sure what you are saying, but I think you are misunderstanding what the Table represents. I infer by your writings, “But the reference to the 3.74 as being attributable to the "Chernobyl nuclear disaster" is inaccurate...”, to mean that a 3.74 quake caused the "Chernobyl nuclear disaster".

If so, you misunderstand what the table is conveying. The table conveys that the energy release of the “major explosion at the plant; that is the 40 GJ impact experienced”, is equivalent to a 3.74 quake energy release on the Richter scale. That is, a quake did not caused the “event”.

The information comes from Wikipedia not myself. However, if I or anyone else is misunderstanding your statement, please provide us with more information. I for one would love to here form an expert in nuclear engineering and accident risk assessment. Your expertise would help us more understand the energy release of nuclear devises and how we perceive them.

Greg Glover (talk) 21:34, 22 March 2011 (UTC)

Pepcon/Toba

Well, if you look at the numerous videos of the Pepcon disaster, it's clear that the explosion was far bigger that the 6.6 tons mentionned here. Concerning Toba, the TNT equivalent of 800 Mt is way too low (the reference "Middle Paleolithic Assemblages from the Indian Subcontinent Before and After the Toba Super-eruption" never mentions this number). Remember that the caldera is 100x30 km. That would be OK for the 1815 Tambora explosion. Toba was originally estimated to be a 1 TT (= 1000 GT) event. —Preceding unsigned comment added by 81.62.29.178 (talk) 22:54, 26 March 2011 (UTC)

Technically there is no such thing as a "Richter Scale"

Dear all, it may come as a surprise to you, but the term "Richter scale" has been invented by journalists and is technically incorrect. The term has been widely used in the media to describe two different scales: the local, ML, and the surface wave, Ms, scales. These latter terms are correct and specific. I am a seismologist trained by C. F. Richter at the seismo lab of CALTECH, so this is one thing I know about.

What should we do to educate the public correctly, as some one requested in the discussion? I think the major points we should get across, and that are not yet covered adequately in this article, are the following.

1) All magnitude scales for earthquakes are designed to be the same and attempt to give one number measuring the size of an earthquake.

2) There are different scales because at different distance from the earthquake there are different types of waves available for measuring the amplitude.

3) Although all scales are supposed to be equivalent, they are not quite the same, and there are reasons for this.

4) Some scales saturate for large earthquakes and there is a physical reason for this, which we should explain.

5) The surface wave magnitude has been the most important, most widely used for earthquakes worldwide and for decades. It must be mentioned in the lead paragraph.

6) The article should explain why the moment magnitude, Mw, has a physical meaning (in contrast to the other magnitudes), and what it takes to derive Mw.

There is much correct and informative material in this article, but it can be improved. I propose to straighten out this article and then to ask another professional seismologist to go over it and improve what may be stated better.MaxWyss (talk) 15:52, 15 April 2011 (UTC)MaxWyss

I forgot to mention that there are a couple of errors which need to be corrected. For example Ms and Mw do not measure the elastic energy released by an earthquake, they measure the moment (although both quantities have units of energy, they are not the same).MaxWyss (talk) 16:11, 15 April 2011 (UTC)MaxWyss

I have now replaced the summary paragraphs with correct text and with about the same scope of depth of explanations, although some things are now explained that were puzzling readers before.MaxWyss (talk) 17:15, 15 April 2011 (UTC)MaxWyss

The graph in this article

I am sorry, but I request that the graph be removed. The following is wrong with it at a glance:

1) There is no source given.

2) As origin "own work" is given by the author, thus it does not qualify for wikipedia, as I understand it.

3) The right hand axis is labeled "Energy / J". It is not per J, but should be "Energy (J).

4) The figure caption is poorly worded and not quite right.

5) The justification and explanation of the figure is grammatically as well as factually incorrect, sorry author, but that does not cut it.

6) No indication is given for what volume these numbers are supposed to be valid.

7) If the volume is the planet Earth, then all numbers of events below magnitude 5 are pure conjecture. Earthquakes of these sizes are not recorded for the Earth, only for very densely instrumented areas like parts of Japan, California, and Iceland, for example.MaxWyss (talk) 22:03, 15 April 2011 (UTC)MaxWyss

Sorry it's taken me so long to look at it Max, I've removed it as a pretty clear case of WP:OR - apart from all the other issues that you've identified. Mikenorton (talk) 18:23, 14 November 2011 (UTC)

2011 Virginia earthquake

Is there any reason to delink this quake (done within the past 12 hours) and move its magnitude to an unsubstantiated figure? — Glenn L (talk) 01:54, 25 August 2011 (UTC)

The base of the richter scale

It says on the article that the Richter scale is a base-10 logarithmic scale. Well I am studying geology at University and my lecturer, who is an acclaimed geologist, told us today that it is actually a base 31.5 scale. He has done a lot of research on Charles Richters scale and he said that many people are under the WRONG impression that it is a base-1o scale, something which in particular the press have emphasised! Obviously i dont have any references however I am concerned because this quite important fact is actually Incorrect and so compromises this article accuracy?! Colinmotox11 (talk) 20:01, 16 September 2011 (UTC)

Heres some proof - http://www.londoninternational.ac.uk/current_students/programme_resources/lse/lse_pdf/foundation_units/physical_geog/physicalgeog_chap1.pdf — Preceding unsigned comment added by Colinmotox11 (talk • contribs) 20:25, 16 September 2011 (UTC)

Hey are you sure about this? In any onther source u can see on the net the base is given as 10.Just to make sure — Preceding unsigned comment added by 59.93.4.130 (talk) 14:31, 24 September 2011 (UTC)

It's still a base-10 logarithmic scale based on "amplitude" and not energy release. The only difference is that the increase is 1.5 times the base-10 log of the energy release rather than simply the base-10 log. Also, 10 ^ 1.5 is actually just over 31.62 (the square root of 1000, slightly under 31 + 5/8) instead of the 31.5 figure (the approximate square root of 992) given in the cited textbook. — Glenn L (talk) 15:34, 24 September 2011 (UTC)

Good afternoon Glenn L,

As I have stated earlier. I can't do logarithms. I see that you can. As I perceive over the last several months the community has adopted my compromise.

Can you go to #36 Richter magnitudes based on 2.0 MJ and double check the math? Greg Glover (talk) 21:34, 28 September 2011 (UTC)