• 1
  • 3
  • 4
  • 5

SEISMIC REFRACTION

Seismic refraction is a useful method for investigating geological structure and rock properties. The technique involves observation of a seismic signal that has been refracted from underlain layers of higher seismic velocities. Shots are generated using a hammer/explosive source at the ground surface and the resulting body waves are recorded via a linear array of geophone sensors. The travel-times of refracted signals are derived from the data and are then processed to determine depth profiles of the targeted geological boundaries.

Typical Targets

  • Alluvium and bedrock profiling,
  • Detection of buried channels,
  • Measuring of rock strength,
  • Water table detection.

Benefits of seismic profiling

  • Cost effective,
  • High productivity,
  • Continuous profiling,
  • Non-destructive,
  • Environment friendly.

 SEISMIC REFLECTION

ZAP Consulting Engineers has specialist experience in the design and implementation of high resolution seismic reflection surveys for onshore and transition zone environments. The company routinely carries out seismic survey work for geotechnical and environmental applications as well as larger scale work for oil/mineral exploration.

BOREHOLE SEISMIC METHODS

Borehole seismic surveying is an important method for determining key in-situ subsurface information and utilized in a variety of geotechnical site investigations, including earthquake site response modeling, foundation design for dynamic loads and rock quality assessment. Borehole seismic data provides detailed information on stratigraphy and the engineering properties of subsurface soils and rocks that are not available from surface seismic surveys and thus are often used for the enhancement and quality control of surface seismic interpretations. Borehole seismic methods largely fall into three categories, namely, down-hole, up-hole and cross-hole.

In down-hole surveys, seismic signals generated at ground surface, are recorded at regular depth intervals in a borehole, while in up-hole method, source is lowered in the hole and sensors are located at the surface. In cross-hole technique, both source and receivers are located in two separate boreholes and signals travelling between holes, are recorded. Cross-hole surveys are often used to perform high resolution seismic tomography.

Typical Targets

  • Geological hazards,
  • Fracture zones,
  • Caves/ stops/ audits,
  • Measuring elastic parameters.

 Benefits of Borehole Seismic

  • Cost effective,
  • Images between boreholes,
  • Non-invasive,
  • Environment friendly,
  • Good productivity.

 

 

 

 

Print Friendly