# Richter scale

• May 10th 2010, 05:18 AM
DenOnde
Richter scale
Hi!

I would really appraciate som help with this following problem. My apologies if this is en the wrong thread but im a swede and my english terms in mathematics isn't all that great :P

$
M = 2/3(log10E-4.4)
$

M is the magnitude and E the energy which is released during and earthquake.

> Solve this equation with respect to E..

> A powerful earthquake has the magnitude 8.0 on the Richterscale. How much energy i released in such an earthquake?

I've started with this one:
$8.0 = 2/3(log10E-4.4)$
$12 = log10E-4.4$
$16.4 = log10E$

and now im stuck :)

Any help regarding these two tasks would be great :)

Best Regards
• May 10th 2010, 05:36 AM
BobBali
$Log10E = 16.4
Log10E = Log 16.4$
Take log of the other side of the equation

E = Log16.4/Log10[/tex]

E = 1.2148

Hope it helps.
• May 10th 2010, 05:46 AM
DenOnde
thank you for the quick reply!

I thought this was the next step but i got confused regarding the result.

Isn't it to small? 1.21... Joule sounds very little when it supposed to be a big earthquake?

thx again
• May 11th 2010, 04:14 AM
HallsofIvy
BobBall was thinking that your "log10E" was "logarithm of 10 times E" when I think you meant " $log_{10}E$, the "logarithm, base 10, of E".

So from $log_{10}E= 16.4$ use the inverse logarithm ( $10^x$ on a calculator to get 25118864315095801, approximately.