Seismology is the study of earthquakes and seismic waves. Seismic waves are vibrations generated by earthquakes or explosions that propagate within the Earth. A seismograph records the magnitude of ground oscillations caused by seismic waves. There are two main types of seismic waves - body waves that travel through the Earth's interior and surface waves that travel along the Earth's surface. Body waves include P-waves and S-waves, while surface waves include Love waves and Rayleigh waves.

2. Seismology is a branch of geophysics
which concerned with study of
earthquakes and transmission and
dissemination of seismic waves within the
Earth.
Seismic waves are vibrations that are
usually generated by earthquakes or
explosions and are propagated within the
Earth or along its surface.

3. A seismograph records varying magnitude of
ground oscillations caused by seismic waves that
travel from their point of origin through the
Earth or along its surface.
Magnitude is the measure of the energy
released at the source of the earthquake and it is
expressed using the Richter scale.
In 1935, Charles F. Richter of the California
Institute of Technology developed a
mathematical device to measure and compare
the magnitude of earthquakes.

5. Types of Seismic Waves
A. Body Waves – it travel through the Earth’s
mantle and crust.
1. primary waves (also called P waves) –
are the fastest of all the seismic wave types and
produce longitudinal movement (in the same
direction of the wave propagation).
2. S wave or secondary waves (also
called shear waves) – moves through the body
of the earth but are slightly slower than P
waves and produced perpendicular wave
motion, unlike P waves, cannot travel through
liquid.
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6. B.Surface Waves
1. Love Waves (1911, Augustus Edward
Hough Love) – Move the ground from side to
side in a horizontal plane but at right angles
to the direction of propagation. The
horizontal shaking of Love waves is damaging
to the foundations of structures.
2. Rayleigh Waves (1885, Lord
Rayleigh) – this wave moves like rolling ocean
waves. In addition it moves both vertically
and horizontally in a vertical pane pointed in
the direction in which the waves are
travelling.