Answer:
M = Log (10S/S)
Explanation:
We are told that the magnitude, M, of an earthquake is defined to be;
M = Log l/S
Where I is intensity and S is standard earthquake.
Now, we want to find the magnitude of an earthquake that is 10 times more intense than a standard earthquake
Since 10 times more intense than standard earthquake, it means that;
I = 10S
So plugging in 10S for I in the original equation for magnitude gives;
M = Log (10S/S)