Magnetic anomalies are variations in the Earth's magnetic field that differ from the expected values. These anomalies can occur due to differences in the composition of rocks, the presence of minerals, or geological structures beneath the Earth's surface. Scientists study these anomalies to understand the Earth's crust and its geological history. These anomalies are often measured using instruments like magnetometers, which detect changes in magnetic intensity. Geophysicists use this data to locate resources such as minerals and oil, as well as to study tectonic activity and the movement of tectonic plates.