$\"\"$

The magnitude function is $\"\"$ .

Where, the magnitude of an earthquake is $\"\"$ .

$\"\"$ is the reading of a zero-level earthquake the same distance from its epicenter.

An earthquake whose seismographic reading measures $\"\"$ millimeters.

Find the magnitude of earth quake when seismographic reading of $\"\"$ millimeters $\"\"$ kilometers from the center.

Therefore, $\"\"$ .

The magnitude function is $\"\"$ .

Substitute $\"\"$ and $\"\"$ in the above equation.

$\"\"$

The magnitude of an earthquake is $\"\"$ .

$\"\"$

The magnitude of an earthquake is $\"\"$ .