Introduction – Basic geophysical properties of the Earth. Theory of elasticity – Seismograph. Seismic waves and their propagation in the Earth’s interior. Reflection seismology – Refraction Seismology. Structure of the Earth’s interior. Seismic faulting – Focal mechanism of the earthquakes.Earthquake magnitude.Seismicity – Macroseismic effects.Earthquake prediction.Main geophysical features in Greece.