It combines physics and geology to study the Earth's physical properties, such as:

* Composition: Studying the materials that make up the Earth's interior and surface.

* Structure: Understanding the layers of the Earth and their properties.

* Processes: Investigating the forces that drive geological processes, like plate tectonics, earthquakes, and volcanoes.

* Fields: Examining the Earth's magnetic field, gravitational field, and electrical conductivity.

Therefore, geophysics is considered a sub-discipline of Earth science focusing on the physical aspects of our planet.