DYNAMIC PROPERTIES OF ROCKS
Outline of Discussion
• Types of Waves
• Factors influencing wave velocity (S- and P-waves)
• Static & Dynamic Moduli of Elasticity
• How to measure these dynamic properties of soils/rocks
• Application – Grouting
* Types of Waves
• Body waves – travelling /propagating within the earth.
• Surface waves – Travelling/propagating on the surface of the earth.
*Types of BODY Waves
S-wave is a shear wave. Also a transverse wave. It is the second wave to detect by the seismograph (the
reason why it is called “secondary”). Unlike P-wave, S-wave cannot travel on fluids.
P-wave is a compressional wave. It is also a longitudinal wave. P-wave or Primary wave has the fastest
velocity and the first wave to detect by the seismograph (the reason why it is called “primary”).
* Types of Surface Waves
Rayleigh wave also known Rolling wave. It causes the rolling motion of the particles of the earth’s
surface during earthquake.
Love wave also known as Q-wave (Quer: German word for lateral) Love wave cause the horizontal
shifting of the earth’s surface during earthquake. It travels slower than P-wave and S-wave but faster
than Rayleigh wave.
*NOTES
P motion travels fastest in materials, so the P-wave is the first-arriving energy on a seismogram.
Generally smaller and higher frequency than the S and surface waves. P-waves in a liquid or gas are
pressure waves, including sound waves.
S-waves do not travel through fluids, so do not exist in Earth's liquid outer core or in air or water or
molten rock (magma). S-waves travel slower than P-waves in a solid and, therefore, arrive after the P-
wave.
Love waves exist because of the Earth's surface. They are largest at the surface and decrease in
amplitude with depth. Love waves are dispersive, that is, the wave velocity is dependent on frequency,
with low frequencies normally propagating at higher velocity. Depth of penetration of the Love waves is
also dependent on frequency, with lower frequencies penetrating to greater depth.
Rayleigh waves are also dispersive and the amplitudes generally decrease with depth in the Earth.
Appearance and particle motion are similar to water waves.
Outline of Discussion
• Types of Waves
• Factors influencing wave velocity (S- and P-waves)
• Static & Dynamic Moduli of Elasticity
• How to measure these dynamic properties of soils/rocks
• Application – Grouting
* Types of Waves
• Body waves – travelling /propagating within the earth.
• Surface waves – Travelling/propagating on the surface of the earth.
*Types of BODY Waves
S-wave is a shear wave. Also a transverse wave. It is the second wave to detect by the seismograph (the
reason why it is called “secondary”). Unlike P-wave, S-wave cannot travel on fluids.
P-wave is a compressional wave. It is also a longitudinal wave. P-wave or Primary wave has the fastest
velocity and the first wave to detect by the seismograph (the reason why it is called “primary”).
* Types of Surface Waves
Rayleigh wave also known Rolling wave. It causes the rolling motion of the particles of the earth’s
surface during earthquake.
Love wave also known as Q-wave (Quer: German word for lateral) Love wave cause the horizontal
shifting of the earth’s surface during earthquake. It travels slower than P-wave and S-wave but faster
than Rayleigh wave.
*NOTES
P motion travels fastest in materials, so the P-wave is the first-arriving energy on a seismogram.
Generally smaller and higher frequency than the S and surface waves. P-waves in a liquid or gas are
pressure waves, including sound waves.
S-waves do not travel through fluids, so do not exist in Earth's liquid outer core or in air or water or
molten rock (magma). S-waves travel slower than P-waves in a solid and, therefore, arrive after the P-
wave.
Love waves exist because of the Earth's surface. They are largest at the surface and decrease in
amplitude with depth. Love waves are dispersive, that is, the wave velocity is dependent on frequency,
with low frequencies normally propagating at higher velocity. Depth of penetration of the Love waves is
also dependent on frequency, with lower frequencies penetrating to greater depth.
Rayleigh waves are also dispersive and the amplitudes generally decrease with depth in the Earth.
Appearance and particle motion are similar to water waves.
