Geophysics:
The study of the Earth using physics, including its gravity, magnetic field, seismic activity, and more.
Seismology:
A specific area within geophysics that focuses on earthquakes, the generation of seismic waves, and how they propagate through the Earth.
Geodesy:
A branch of geophysics that studies the geometrical, structural, and gravitational properties of the Earth, and their evolution over time.