One way to measure an earthquake is by its magnitude, or strength, on the Richter scale.
Another way is to measure its intensity. Intensity shows how bad the damage was. That includes things like fallen buildings and lost lives. These measurements can be very different. For example, an earthquake of small magnitude can do a lot of damage if the area isn’t ready for it.
How do we measure intensity? With the Modified Mercalli Intensity Scale. It was invented in 1902 by Italian seismologist Giuseppe Mercalli. The scale uses numbers to help explain events. It ranges from I (not felt) to XII (total destruction).
We measure magnitude with a seismograph. That’s a device for recording vibrations in the Earth. A weight inside it hangs down and stays still, even when the Earth moves. The rest of the seismograph does move. That movement is written down by a pen and paper connected to the machine.
