find energy released in quake, given magnitude of quake

wilc0919

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Oct 13, 2006
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I am totally LOST here: PLEASE Explain in detail and help me answer this...please.

Question: The magnitude M on the richter scale is given by the equation below where E is the energy released (in joules) and E base 0 = 10^4.4 joules. If the magnitude M of the 1906 San Fran quake was 8.2, how much energy was released in joules?

M= 2/3 log E/E base 0

Please help!
 
By "base 0", do you mean "subscript zero"? That is, "the initial, or reference, or baseline, value"? I will assume so.

By "M= 2/3 log E/E base 0", do you mean any of the following?

. . . . .M = 2 / (3 log(E) / E<sub>0</sub>))

. . . . .M = 2 / (3 log(E / E<sub>0</sub>))

. . . . .M = (2/3)(log(E) / E<sub>0</sub>))

. . . . .M = (2/3)(log(E / E<sub>0</sub>))

Or something else?

You have been given a formula, and you have been given the values for M and for E<sub>0</sub>. You have then been asked for the value of E. So plug the given values into the given formula, and solve for the value of the remaining variable.

If you get stuck, please reply showing all of your work and reasoning, starting from a clarified version of the formula, and showing what you plugged in, where. Thank you.

Eliz.
 
don't understand your examples

it is

m = 2/3 log E/E with the little o on the bottom of the bottom E
 
wilc0919 said:
it is m = 2/3 log E/E with the little o on the bottom of the bottom E
I'm sorry, but all you did was change the case on the letter "M". You didn't clarify what is grouped with what. Since the answer will depend upon such things as "is the log in the denominator, along with the 3?", and since we cannot tell from what you have posted, I'm afraid it will be difficult to provide specific instruction.

Please reply showing what you have done so far, starting with the equation, and then showing the equation with the values plugged in. Thank you.

Eliz.
 
referring to original post

plugging in the M and the E with a little 0 near it's bottom (don't know how to illustrate that point)


I come up with

8.2 = 2/3 log E/10^4.4

Can you help me past this point....I keep getting different answers....can you just illustrate how I need to set it up please?
 
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