What do we mean when we say that scales of earthquake magnitude are logarithmic scales rather than linear?

Question

scales?

Answer 1

They go up by a factor of 10 each time, like a 5 on the richter scale is 1000 times more powerful than a 4 I think.

Logs are used, they are base 10.

Answer 2

The number on the Richter scale that everyone talks about after an earthquake is actually the base 10 log of amount of dynamite that would have to be set off to get that much energy. The reason a log is used is because earthquakes can be very different in their power and increase exponentially. The log basically used to turn a messy set of exponential data into a nice, straight line so that you can see relationships when you plot it on a graph against other data.

What this means to you is that you get a nice linear scale, called the Richter scale, to refer to earthquakes by. However, it is important to remember that there was a log involved. Since the log was a standard base 10 log; an earthquake that is given a 7 is 10 times more powerful than a 6, a 6 is 10 times more powerful than a 5, and so on.

Earthquakes aren't the only thing measured on a logarithmic scale. Two more that come to mind are pH for measuring acids and bases, and the decibel scale for loudness.

Answer 3

A logarithmic scale means that each number is more than just one above the previous number. A linear scale would be a ruler: - 6 inches is 1 inch more than 5 inches A logarithmic scale would be earthquake magnitudes: - an earthquake of magnitude 5.0 is 10 times more powerful than one of magnitude 4.0

Answer 4

Please visit my slide show at URL
http://asia.pg.photos.yahoo.com/ph/quake
to know more on Richter scale.The earthquake releases the energy at some places in hundreds tonnes of TNT equal of energy. Whereas at some places the energy release is equivalent to several million tonnes. To make the common people to under stand its effect Mr Charles Richter has found a method by which the force released can be denoted in simple number.By using logarithmic scale and base as ten This measurements are calculated by the arrival time of P and S waves ( to know the distance of epicenter) and the maximum amplitude recorded in the seismograph. The shaking will increase by ten fold for each Richter scale. Suppose if you measure the earthquake of Richter scale 3 from a distance of 100 kilometers the maximum shaking recorded in the seismograph will be 0.1 mm. If you measure the earthquake for 4 on Richter scale from the same 100 K / M distance the shaking will be ten times more that is 1 mm. But the increase in energy release is about 32 times higher for each Richter scale. The amount of shaking should not be confused with the amount of energy released.

Answer 5

Each tenth of a point increase in magnitude is a tenfold increase in intensity.