Tiltmeters act like highly advanced carpenter’s levels. They often use a bubble of gas in a liquid or a laser system to track changes in the Earth’s slope to within a fraction of a millimeter. While they cannot predict when an earthquake will happen, they are essential for monitoring “geodetic” changes. In volcanic regions, a rising tiltmeter reading suggests that magma is inflating the mountain, while along a fault, it indicates that the plates are bending under extreme elastic strain, providing vital data for hazard assessment and long-term monitoring.