<span title="Intensity/Magnitude-----EARTHQUAKE">Intensity/Magnitude-----E...</span> Problem?

Question

The 1906 San Francisco earthquake had a magnitude of 8.3 on the Richter scale. At the same time in South America there was an earthquake with magnitude 5.2 that caused only minor damage. How many times more intense was the San Francisco earthquake than the South American one?

I need the Formula for this problem and please show me how to do it...

*IF POSSIBLE I ALSO NEED Half-life formula..

THANKS!!

Answer 1

The Richter magnitudes are based on a logarithmic scale (base 10). What this means is that for each whole number you go up on the Richter scale, the amplitude of the ground motion recorded by a seismograph goes up ten times. Using this scale, a magnitude 5 earthquake would result in ten times the level of ground shaking as a magnitude 4 earthquake (and 32 times as much energy would be released).

Can you figure it out from the above?  If not, add details and I will come back and check your question.

Forgot the half life formula--sorry.

Go to:

http://en.wikipedia.org/wiki/Half-life

Answer 2

It&#039;s a logarithmic scale, so the SF earthquake is 10^8.3/10^5.2  = 10^(8.3-5.2) = 10^3.1 times stronger.

For radioactive decay N = N0*exp(-lambda*t)

You can figure out what lambda is by plugging for the half life.

EDIT: Initially I had made a very stupid math typo, dividing instead of subtracting exponents.

Answer 3

10^8.3 compared to 10^5.2

It was 1260 times as strong.

Half life is explained right here in more detail: http://en.wikipedia.org/wiki/Half-life but it refers to the time that it takes for 1/2 of the mass of a specimen to decay.

Answer 4

I am giving below the energy release for each Richter scale up to 10. We have not yet experienced more than 9.5 on Richter scale.It is called open ended scale.No upper limit for it. The force released at the point of focus only given in Richter scale. Therefore the real damage may not be directly connected with Richter scale. Each is releasing 31.7 times more energy than the lower scale. But the shaking will increase only by ten times for each Richter scale and will get reduced as the disatances increases from epicenter in the rate of inverse square of the distance.

 For body wave

       mb = log V p-wave +0.01delta+5.1

                    For surface wave

Ms = log V surface-wave + 1.66log delta+2.5



   where V is the velocity of the wave in micrometers/sec, and (Delta) is the angular epicentral distance in degrees.

Approximate TNT (Tri nitro telecom )  Yield for Seismic Energy                    

                       Richter scale

                                   1                     30 lbs  

                                   2. 1 ton

     3. 29 ton

     4. 1000 ton

     5. 32000 ton

     6. 1 million ton

     7. 32 million ton

     8. 1 billion ton

     9. 32 billion ton

    10 1 trillion ton.