Fiveable
Fiveable
Fiveable
Fiveable

Geophysical survey design is crucial for successful field investigations. It involves selecting appropriate methods, defining parameters, and planning data acquisition strategies based on project goals and site conditions. Proper planning ensures efficient data collection and high-quality results.

Key factors in survey design include geological considerations, site conditions, and project objectives. Balancing these factors with practical constraints like budget and time is essential. A well-designed survey optimizes methods, parameters, and logistics to achieve the best possible outcomes within project limitations.

Survey Design Principles

Selecting Appropriate Methods and Parameters

Top images from around the web for Selecting Appropriate Methods and Parameters
Top images from around the web for Selecting Appropriate Methods and Parameters
  • Survey design involves selecting appropriate geophysical methods, defining survey parameters, and determining data acquisition strategies based on project objectives and site conditions
  • Principles of survey design include considering the target depth, size, and physical properties, as well as the desired resolution and spatial coverage
  • Choose geophysical methods that are sensitive to the physical properties of the target and can provide the required depth of investigation and resolution (seismic reflection for deep sedimentary layers, ground-penetrating radar for shallow buried objects)
  • Define survey parameters, such as station spacing, sampling interval, and recording time, to ensure adequate spatial and temporal resolution of the target

Logistics and Data Acquisition Planning

  • Survey planning involves logistics, such as equipment selection, survey grid layout, and data acquisition protocols, to ensure efficient and effective data collection
  • Select equipment that is suitable for the chosen geophysical methods and can operate effectively in the site conditions (rugged terrain, high-temperature environments)
  • Design survey grid layout to provide optimal coverage of the target area, considering factors such as accessibility, topography, and potential sources of interference
  • Establish data acquisition protocols, including measurement procedures, quality control measures, and documentation requirements, to ensure consistent and reliable data collection
  • Proper survey design and planning are critical for obtaining high-quality geophysical data that can be effectively interpreted to address the project objectives

Factors in Survey Design

Geological and Site Considerations

  • Geological factors, such as the expected subsurface structure, lithology, and physical properties of the target and surrounding materials, influence the choice of geophysical methods and survey parameters
  • Consider the expected depth, geometry, and composition of the target, as well as the properties of the overburden and bedrock (electrical resistivity, seismic velocity, magnetic susceptibility)
  • Site conditions, including topography, accessibility, vegetation, and cultural features, can impact survey design and data acquisition strategies
  • Assess the potential impact of site conditions on data quality and logistics, such as the presence of steep slopes, dense vegetation, or sources of cultural noise (power lines, pipelines)

Project Objectives and Constraints

  • Project objectives, such as the desired depth of investigation, spatial resolution, and target characteristics, guide the selection of appropriate geophysical methods and survey parameters
  • Define clear objectives for the geophysical survey, such as mapping subsurface geology, detecting buried objects, or characterizing groundwater resources
  • Determine the required depth of investigation and spatial resolution based on the expected size and depth of the target (detecting small-scale features may require higher resolution than mapping regional geology)
  • Budget, time constraints, and available resources are practical considerations that influence survey design and the extent of data acquisition
  • Optimize survey design to balance project objectives with available resources, such as selecting cost-effective methods, prioritizing survey areas, or phasing data acquisition

Comprehensive Survey Planning

Defining Objectives and Selecting Methods

  • Define clear project objectives and identify the geophysical target(s) of interest, including their expected depth, size, and physical properties
  • Select appropriate geophysical methods based on the project objectives, target characteristics, and site conditions, considering the strengths and limitations of each method
  • Choose methods that are complementary and can provide independent information about the target (combining seismic and electrical methods to characterize both structure and composition)
  • Consider the cost, time, and logistical requirements of each method, as well as the availability of equipment and expertise

Survey Geometry and Data Acquisition

  • Determine the survey area, grid layout, and station spacing to ensure adequate spatial coverage and resolution, considering the expected target size and depth
  • Design survey geometry to optimize the detection and resolution of the target, such as using 3D survey grids for complex structures or dense station spacing for high-resolution imaging
  • Establish data acquisition parameters, such as sampling interval, recording time, and source-receiver configurations, to optimize data quality and efficiency
  • Select parameters that balance the need for high-resolution data with the practical constraints of data acquisition, such as using longer recording times for deep targets or shorter sampling intervals for high-frequency signals
  • Plan for data quality control measures, such as repeat measurements, calibration, and noise reduction techniques, to ensure the reliability of the acquired data

Documentation and Quality Control

  • Document the survey plan, including the selected methods, survey parameters, and data acquisition protocols, to ensure consistency and reproducibility
  • Create clear and detailed documentation of the survey design, including maps, diagrams, and tables of survey parameters and locations
  • Establish quality control procedures, such as daily equipment checks, calibration measurements, and field data review, to identify and address any issues during data acquisition
  • Plan for data backup and storage, including secure data transfer and archiving, to prevent data loss and ensure long-term accessibility

Limitations and Errors in Design

Method Limitations and Site Effects

  • Recognize the inherent limitations of each geophysical method, such as the depth of investigation, resolution, and sensitivity to different physical properties
  • Consider the limitations of seismic methods in areas with high attenuation or poor signal transmission, or the limitations of electrical methods in highly resistive or conductive environments
  • Consider the potential impact of site conditions, such as topography, vegetation, and cultural noise, on data quality and interpretability
  • Assess the effect of topographic variations on data acquisition and processing, such as the need for terrain corrections in gravity surveys or the impact of elevation changes on seismic travel times
  • Evaluate the potential for cultural noise, such as power lines, pipelines, or nearby traffic, to interfere with data acquisition and interpretation

Survey Geometry and Parameter Selection

  • Identify potential sources of error in survey design, such as inadequate spatial sampling, incorrect assumptions about target properties, or inappropriate method selection
  • Assess the effect of survey geometry, including the orientation and spacing of survey lines and stations, on the ability to detect and resolve the target(s) of interest
  • Consider the impact of survey orientation on the detection of anisotropic properties or the resolution of complex structures (using survey lines perpendicular to the strike of geological layers)
  • Evaluate the trade-offs between survey parameters, such as the balance between spatial coverage and resolution, and their impact on data quality and interpretation
  • Assess the impact of station spacing on the ability to detect small-scale features or resolve lateral variations in physical properties

Mitigation Strategies

  • Develop strategies to mitigate potential sources of error, such as incorporating redundant measurements, using multiple geophysical methods, or adapting the survey design based on preliminary data analysis
  • Use redundant measurements, such as reciprocal or repeat measurements, to assess data quality and identify potential errors or inconsistencies
  • Employ multiple geophysical methods to provide independent information about the target and reduce the impact of method-specific limitations or uncertainties
  • Adapt the survey design based on preliminary data analysis, such as adjusting survey parameters or expanding the survey area to better characterize the target or resolve unexpected features
  • Incorporate data processing techniques, such as filtering, smoothing, or inversion, to enhance data quality and reduce the impact of noise or artifacts


© 2025 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.

© 2025 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.
Glossary
Glossary