Magnetic anomalies are variations in the Earth's magnetic field that differ from the expected normal values. These anomalies can be caused by geological formations, such as volcanic rocks or metallic minerals, which can either enhance or diminish the magnetic field in a specific area. Scientists study these anomalies to gain insights into the Earth's structure and composition. Magnetic anomalies are often measured using magnetometers, which detect changes in magnetic intensity. They are important in various fields, including geology, archaeology, and mineral exploration, as they help identify potential resources and understand the Earth's history.