Seismic waves propagate through elastic media and are used to locate mineral and oil deposits, groundwater, archaeological sites, and detect properties of geological structures. The document discusses stress and strain in rocks, defining stress as a measure of internal forces balancing external forces applied to a body, and strain as the relative deformation of a body under stress. Stress can be normal, shearing, hydrostatic, or tensile, and is defined by nine components; strain includes shear and dilation or contraction.

1. Locate mineral and oil deposits. o Also deals with the detection of groundwater horizons,
geothermal reservoirs, archaeological sites and construction sites. Period / Frequency Wave Motion
Seismic waves: Propagation through elastic media. Need to understand the elastic properties of a
medium. Initially assume that the rock body is homogeneous and isotropic (although the world is
not always). Need to understand stress and strain of rocks. When external forces are applied to a
body, internal forces are set up within the body to counteract the external forces and deformation of
the body (its geometrical shape) Stress Is a measure of the intensity of these balanced internal
forces. Stress may be resolved into:a component of normal stress perpendicular to Downloaded by
Koyyee Keenya (koyye2030@gmail.com) lOMoARcPSD|36158067 the surface a component of
shearing stress in the plane of the surface Nine stress components are needed to define the stress
at any point. (tensor) Compressive: forces directed towards each other Tensile: forces are
directed away from each other Hydrostatic: when all normal stresses are the same Strain Is a
measure of the relative deformation of a body when the body is subject to stress. The change in
shape is expressed per unit length or per unit volume. Can also be defined by nine components
(tensor) Shear Strain: changes shape without changing volume Dilation or contraction: change
in volume without a change in shape

2. Locate mineral and oil deposits. o Also deals with the detection of groundwater horizons,
geothermal reservoirs, archaeological sites and construction sites. Period / Frequency
Wave Motion Seismic waves: Propagation through elastic media. Need to understand
the elastic properties of a medium. Initially assume that the rock body is homogeneous
and isotropic (although the world is not always). Need to understand stress and strain
of rocks. When external forces are applied to a body, internal forces are set up within the

3. • body to counteract the external forces and deformation
of the body (its geometrical shape) Stress Is a
measure of the intensity of these balanced internal
forces. Stress may be resolved into:a component of
normal stress perpendicular to Downloaded by Koyyee
Keenya (koyye2030@gmail.com)
lOMoARcPSD|36158067 the surface a component of
shearing stress in the plane of the surface Nine stress
components are needed to define the stress at any point.
(tensor) Compressive: forces directed towards each
other Tensile: forces