GEOPHYSICAL METHODS Flashcards
(17 cards)
non-invasive techniques used to investigate subsurface properties and structures.
GEOPHYSICAL METHODS
rely on measuring and analyzing physical properties such as electrical, magnetic, gravitational, and seismic characteristics to provide information about the subsurface.
GEOPHYSICAL METHODS
5 GEOPHYSICAL METHODS
1.Ground Penetrating Radar (GPR)
2.Electrical Resistivity Tomography (ERT)
3.Magnetometry
4.Gravity Surveys
Seismic Methods
uses electromagnetic waves to image subsurface features. It emits high-frequency radio waves into the ground and detects the reflections caused by variations in subsurface materials
Ground Penetrating Radar (GPR)
is effective in locating buried utilities, detecting voids, mapping bedrock, and determining changes in soil stratigraphy.
Ground Penetrating Radar (GPR)
- measures the electrical resistivity of subsurface materials. By injecting electrical current into the ground and measuring the resulting voltage, engineers can determine variations in resistivity.
Electrical Resistivity Tomography (ERT)
- is useful in mapping subsurface structures, detecting groundwater levels, and identifying contamination plumes.
Electrical Resistivity Tomography (ERT)
Measures variations in the Earth’s magnetic field caused by subsurface materials with different magnetic properties.
Magnetometry
- By using __________, engineers can identify buried ferrous objects, archaeological features, and subsurface structures.
magnetometers
- is particularly valuable in archaeological surveys and identifying buried metallic utilities.
Magnetometry
measure variations in the Earth’s gravitational field caused by differences in subsurface density.
Gravity Surveys
-are commonly used in geotechnical investigations and mineral exploration.
Gravity Surveys
involve generating and recording seismic waves to study subsurface structures.
Seismic Methods
The two primary seismic techniques used in civil engineering are:
Seismic Reflection
Seismic Refraction
This method utilizes controlled sources of energy, such as hammer strikes or explosives, to generate seismic waves.
Seismic Reflection
The waves reflect off subsurface interfaces and are recorded by receivers (geophones).
___________ is effective in mapping stratigraphy, identifying faults, and determining the depth to bedrock.
Seismic reflection
Involves measuring the travel time and direction of seismic waves that refract at subsurface interfaces due to differences in wave
Seismic Refraction
