# Math Help - One more question..

1. ## One more question..

How would I go about converting intensity to magnitude? (earthquakes)

Richter of 6.1 = 1,258,925.412

But, I am unable to do the opposite! >.<
Intensities:
:39,877,000
:12,589,000
:251,200

If you'd use one for an example, that would be greatly appreciated.

2. Originally Posted by pinnacle2009
How would I go about converting intensity to magnitude? (earthquakes)

Richter of 6.1 = 1,258,925.412

But, I am unable to do the opposite! >.<
Intensities:
:39,877,000
:12,589,000
:251,200

If you'd use one for an example, that would be greatly appreciated.

You have found that:
$10^{6.1} = 1,258,925.412$

What you now need to do is find x when:
$10^x = 39,877,000$

Take the log (base 10) of both sides of the equation to get:

$log(10^x) = log(39,877,000)$

$\therefore x = log(39,877,000) = 7.6$

3. The formula is
$R = \log \frac{I}{I_0}$
where $I_0$ is the intensity of a zero-level earthquake. Looking at this:

Richter of 6.1 = 1,258,925.412
I'm assuming that you're assuming that the intensity of a zero-level earthquake is 1.

So, for an intensity of 39,877,000,
$R = \log 39,877,000 \approx 7.6$.

You can do the other two.

01

EDIT: Beaten to it by Kiwi Dave!