The Mercalli Intensity Scale is a system used to measure the intensity of an earthquake based on its observed effects on people, buildings, and the Earth's surface. Developed by Giovanni Mercalli in 1902, the scale ranges from I (not felt) to XII (total destruction). It provides a qualitative assessment of an earthquake's impact rather than a quantitative measurement of its energy release. This scale helps scientists and emergency responders understand the severity of an earthquake in specific locations. By evaluating reports from witnesses and damage assessments, the Mercalli Intensity Scale aids in disaster response and recovery efforts, ensuring that resources are allocated effectively.