Geophysical sensors are instruments used to measure physical properties of the Earth and its environment. They can detect variations in gravity, magnetic fields, temperature, and seismic activity. These sensors help scientists understand geological processes, locate natural resources, and monitor environmental changes. Common types of geophysical sensors include seismometers, which measure ground vibrations, and magnetometers, which detect magnetic field variations. These tools are essential for applications in geology, environmental science, and engineering, providing valuable data for research and practical uses like earthquake prediction and resource exploration.