Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: VivienneBradtke Home on 26/03/2011 19:30:03
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VivienneBradtke Home asked the Naked Scientists:
Dear NS
While listening to your March 13th podcast and the update on Japan earthquake (http://www.thenakedscientists.com/HTML/podcasts/), I was confused with your language regarding the scale of the earthquake.
Sarah reported that the earthquake had a magnitude of 8.9. then Dave said that is was 8.9 on the Richter scale.
My understanding is that Richter scale can only be used in California and that is "old-hat" and even incorrect to be using it these days.
Can you please clarify and enlighten us all.
Thank you
Vivienne
What do you think?
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The Richter Scale is still a widely used scale of measurement for earthquakes. It is a bit confusing for persons who do not have a mathematics background, being a semi-log scale - http://en.wikipedia.org/wiki/Richter_magnitude_scale
It is however, being phased out IN SCIENTIFIC CIRCLES by the moment magnitude scale. This is much more complicated than the Richter scqale and is rarely used by anyone except scientists. It is even a bit too sophisticated for me since all of the calculus I need has been programmed into the software I use. See http://en.wikipedia.org/wiki/Moment_magnitude_scale for the MM scale. You will see what I mean.
As a result all the news and media outlets still use the Richter scale which is rather easy to explain. In almost all cases, where a magnitude is given, it will be a Richter scale number.
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Thanks Jim
Really helpful answer.
Chris
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As a result all the news and media outlets still use the Richter scale which is rather easy to explain. In almost all cases, where a magnitude is given, it will be a Richter scale number.
According to your Wikipedia notes, the two scales produce similar numbers, but 7+ magnitude earthquakes can not be reliably measured with the Richter scale. Thus, I would assume the media confounds the terminology.
Perception of many natural phenomena follow linearly with changes on a logarithmic scale. So, for example decibels are also measured on a logarithmic scale. So, when you listen to sounds, the difference between a 40 and 50 decibel sound would sound about the same as the difference between a 50 and 60 decibel sound.