Seismicity (Geotechnical)

Seismicity (Geotechnical)2018-09-05T14:00:47+00:00

The intelligent Distributed Acoustic Sensor (iDAS™) can provide critical information on the health of geotechnical structures such as levees, dams, geothermal reservoirs, pipelines.

Transforming a fibre optic cable into a seismic array of unparalleled density, iDAS allows to monitor both ambient-noise-based and stimulated seismicity.

Deploying a fibre optic cable in a shallow subsurface of any geotechnical structure allows for near surface seismic techniques, such as Multichannel Analysis of Surface Waves (MASW) and ambient noise interferometry, to be applied. The information extracted enables to characterise the top 20-40m from the soil surface at unprecedented spatiotemporal resolution and spatial range, while the high time-lapse repeatability of the iDAS allows to detect the appearance of anomalies.

Applications

Seepage/leakage detection

iDAS can localise areas of relative velocity variations of seismic waves imputable to increase/decrease of fluid saturation of soil, as in the case of liquid spilling out of buried pipes, and seepage variations in dams.

Structural Stability

Continuous iDAS monitoring can use ambient-noise to detect early changes from the anticipated response of the geotechnical structure, increasing safety and improving the structure maintenance.

Key Benefits

  • High resolution , continuous health monitoring of geotechnical structures
  • Cost-effective high-resolution seismic array
  • Improved maintenance  and increased on-site safety
  • Easy to install in existing geotechnical structures
geotechnical structures

The reliability of geotechnical structures, such as dams, dikes, levees and geothermal reservoirs requires a rational approach to monitor their condition. iDAS measures the shear wave velocity in soil, which is sensitive to fluid saturation, delivering critical information about any internal erosion that can lead to incidents.

The picture above shows iDAS measurements of shear wave velocity (Vs) in soil.  Vs is sensitive to fluid saturation.