Lecture on Environmental Geophysics PDF
Geology + Physics=Geophysics
Let’s Know the Environmental Geophysics
Environmental geophysics is a relatively new field.
It is primarily used to identify, map or predict the presence and potential movement of surface water and groundwater and to identify contaminants in the soil within the upper 10 to 50 m of the Earth’s surface.
It can also be used to help locate sites for underground waste disposal, examine archaeological sites or even assist the police in their investigations of possible burial sites.
The definition of Environmental Geophysics
Environmental Geophysics can be defined as the application of geophysical methods to the investigation of near-surface physico-chemical phenomena which are likely to have (significant) implications for the management of the local environment.
Application of Geophysical methods in various sectors
Environmental geophysicists often are part of multi-disciplinary teams that include geological engineers, biologists, hydrogeologists, and technicians.
Environmental geophysicists use many of the instruments and techniques used in mining and petroleum geophysics such as magnetic, electrical,l and seismic methods.
Methods applied in Environmental Geophysics
Active
1- Seismic method
2- Electric method
3- GPR method
4- Spontaneous Potential Method
5- Induced Polarisation method
6- Electromagnetic method
Passive
1-Gravity method
2-Magnetic method
| Active (Seismic, Electrical SP, EM etc) | Passive (Gravity, Magnetic) | ||
| Advantage | Disadvantage | Advantage | Disadvantage |
| Better control of noise sources | Field equipment tends to be more complex. | Need supply only a sensor and a data recorder. | Less control of getting noise |
| Active experiments usually provide better depth control over source of anomalous signal. | Field operations and logistics are generally more complex and time consuming | Passive experiments can be run over wider areas in a more cost-effective manner. | Identification of the source of an anomalous observation can be difficult. |
| Active (Seismic, Electrical SP, EM etc) | Passive (Gravity, Magnetic) | ||
| Advantage | Disadvantage | Advantage | Disadvantage |
| Many different source/receiver configurations can be used allowing for a wide variety of survey designs. | Greater survey design costs and potentially leads to increased probability of field mishaps. | Provide the survey on short notice with relatively easily | This limits the amount of customisation that can be done for specific problems. |
| Once set up, active experiments are capable of producing vast quantities of data | Can become overwhelming to process and interpret. | Interpretation can be accomplished quickly and efficiently. | Do not allow a detailed interpretation. |
| Active (Seismic, Electrical SP, EM etc) | Passive (Gravity, Magnetic) | ||
| Advantage | Disadvantage | Advantage | Disadvantage |
| Many different source/receiver configurations can be used allowing for a wide variety of survey designs. | Greater survey design costs and potentially leads to increased probability of field mishaps. | Provide the survey on short notice with relatively easily | This limits the amount of customisation that can be done for specific problems. |
| Once set up, active experiments are capable of producing vast quantities of data | Can become overwhelming to process and interpret. | Interpretation can be accomplished quickly and efficiently. | Do not allow a detailed interpretation. |
What did you learn today?
What is the passive geophysical method?
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- Gravity method
- Seismic method
Lecture By
Dr. Raman Kumar Biswas
Professor
Faculty of Environmental Science and Disaster Management
Patuakhali Science and Technology University
