Which earthquake hazard involves loss of soil strength and fluid-like behavior in saturated sediments?

Which earthquake hazard involves loss of soil strength and fluid-like behavior in saturated sediments?

• A. Ground shaking
• B. Aftershocks
• C. Liquefaction
• D. Tsunami

Answer: (C)

Liquefaction is the process where saturated, loosely packed sediments temporarily lose strength and behave like a fluid during strong ground shaking. Rapid shaking raises pore water pressure inside the soil, which lowers the effective stress that holds the grains together. When effective stress drops enough, the soil can no longer resist shear and it flows, producing fluid-like behavior. This can cause foundations to settle or tilt, ground surfaces to crack or move laterally, and surface features like sand boils or lateral spreading. It requires water-saturated, loose granular soils near the surface and strong seismic shaking. This is distinct from mere ground shaking (the seismic motion itself), aftershocks (subsequent earthquakes), or tsunamis (large ocean waves from seafloor displacement).

Liquefaction is the process where saturated, loosely packed sediments temporarily lose strength and behave like a fluid during strong ground shaking. Rapid shaking raises pore water pressure inside the soil, which lowers the effective stress that holds the grains together. When effective stress drops enough, the soil can no longer resist shear and it flows, producing fluid-like behavior. This can cause foundations to settle or tilt, ground surfaces to crack or move laterally, and surface features like sand boils or lateral spreading. It requires water-saturated, loose granular soils near the surface and strong seismic shaking. This is distinct from mere ground shaking (the seismic motion itself), aftershocks (subsequent earthquakes), or tsunamis (large ocean waves from seafloor displacement).