A seismometer is a seismograph made to measure the direction, intensity, and duration of earthquakes. It does this by measuring the actual movement of the ground.
The Modified Mercalli Intensity (MMI) Scale rates earthquakes acxcording to how much damage they cause at a particular place and the measured ground accelarattions as recorded by a seismomter. In Europe the Macroseismic sclae is used which is similar in concept to the MMI scale.
The scale used to describe the amount of damage an earthquake causes is the Modified Mercalli Intensity (MMI) scale. This scale measures the intensity of shaking and the resulting damage at a specific location, rather than the earthquake's magnitude, which is measured on the Richter scale. The MMI scale ranges from I (not felt) to XII (total destruction), with each level representing a different degree of impact on structures and people.