The term geohazards is used to refer to all failure risks posed to offshore infrastructure by the geological features and process on the seabed.

The most common geohazards are:

  • Situation: Cemented layers and coral outcrops
    Risk: Pile driving problems, Punch through risk, possible jack-up instabilities, damage of pipelines due to movement over hard coral outcorps
  • Situation: Underconsolidation or overconsolidation 
    Risk: During loading the water is unable to move from the pores rendering the soil soft and unstable (liquefaction)
    Overconsolidation is found in the North sea due to the consolidation from the weight of the ice during the ........ period
  • Situation: Active faults
    Risks: Danger of relative movements, gas leakage, damage of drill strings and foundation piles driven through faults, pipeline rupture (bending or axial failure) 
  • Situation: Slope instability, turbitidy currents, debris flow, existing landslides
    Risk: Potentially unstable seabed, landslides, reactivation of landslide
  • Situation: Shallow gas i.e. gas that sweep up from underlying reservoir rocks.
    Risks: Gas escape and blowout, decreased of bearing capacity, reduced achoring capacity of sunction piles, destablilised hydrates 
  • Situation: Mud volcanoes
    Risk:Emmit mud that can burry part of the installation
  • Situation: Fluid vents
    Risks: Decrease bearing capacity, increase pressure inside suction piles.  
  • Situation: Submarine channels
  • Situation: Earthquakes
    Risks: Liquifaction, Stuctural failures, tsunamies