Bedrock localization with deep imaging up to 500 ft/152m

Geophyscal Engineering Monitoring


Map bedrock depth confirmation after drilling campaign.

Bedrock depth was not found by drilling as probably to deep.

Infrastructure monitoring


To secure what will be done, a deep imaging results up to 500 ft/152 m has been realized.

  • Deployments of ultra dense accelerometers array
  • Specific processing of low frequencies

Blue Line 1 : 300 ft/91 m lenght ,  100 sensors, 3 ft/90 cm spacing

Green line 2 : 100 ft/30 m lenght, 100 sensors,  1 ft/30 cm spacing

GEM S-scan


  1. Results show shear wave velocity versus depth up to 200 ft/61 m are consistent between Lines 1 and 2
  2. The results show that there exists deep silt deposit, relatively uniform up to 200 ft/61 m 
  3. Finally the bedrock is deeper than expected and not accessible by drilling or too expensive by this method.
  4. Bedrock position is 220ft/67 m deep.