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Seismics

Near-surface seismics explores the shallow subsurface using methods like refraction, reflection, and surface wave analysis. Data acquisition involves generating seismic waves with sources like hammers, explosives, or vibrators. These waves travel through the ground and are recorded by geophones or seismometers placed at various distances. Refraction analyzes refracted wave travel times for velocity layering, reflection maps subsurface interfaces from reflected waves, and surface waves determine soil stiffness from dispersed wave speeds. The spacing and configuration of sources and receivers are crucial for data quality and resolution. These techniques are essential for environmental studies, critical zone characterization, and understanding subsurface processes related to water resources and contaminant transport.

Geometrics cabled system

  • 1 Stratavizor NZXP:
    • Rugged seismograph with built-in PC containing 48 channels internally. The StrataVisor can be seamlessly expanded by adding Geode modules.

  • 4 Geodes:

    • 24 channels each, modular seismographs designed for high-resolution seismic surveys.

  • 144-channel capability when combining all.

Includes 5-meter and 1-meter spacing cables for varied deployment. Comes with both vertical and horizontal geophones (10 Hz and 4.5 Hz) for pressure and shear-wave velocity characterization.

Geophysical Technology Inc. nodal system

  • 130 Nodes NRU 1C:
    • Autonomous, wireless seismic nodes. The NRU 1C nodes are known for their cable-free operation, simplifying large-scale seismic deployments.
    • Integrated 5 Hz geophones, optimized for low-frequency ground motion detection.
  • 1 EVR-2 Seismic Event Recorder:
    • A standalone event recorder, typically used for monitoring seismic activity or recording specific seismic events.

Soilspy System

  • Soilspy Rosina:
    • A 12-channel surface wave system designed for shallow subsurface characterization.
    • 5-meter spacing cables with vertical geophones.

Seismic Sources

  • Small hammer:
    • Used for high-resolution shallow seismic surveys, providing a high-frequency source.
  • Sledgehammer:
    • A medium-impact source, suitable for deeper investigations than a small hammer.
  • Weight drop (PEG40):
    • A controlled-impact source, providing repeatable energy for shallow to moderate-depth seismic surveys. PEG40 refers to a specific weight drop system.
  • Buffalo gun:
    • A high-energy impulsive source, used for deeper seismic exploration. It typically creates a strong seismic impulse.