Definition

1. Noun:
   • The upper wall of an inclined fault: In geology, the "hanging wall" is the mass of rock that lies above an inclined fault plane. It is the block that would appear to hang over an observer standing within the fault.

Usage

• The term is used specifically in structural geology and mining to describe the relative position of rock blocks along a fault line.
• It is typically paired with its counterpart, the "footwall" (the block below the fault plane).

Examples

• Noun:
  • During the field trip, the geologist pointed out the hanging wall of the thrust fault.
  • Miners must carefully support the hanging wall to prevent collapses in the tunnel.

Advanced Usage

• "Hanging wall collapse": A common hazard in mining where the upper wall of a fault or vein falls.
  • The accident was caused by a sudden hanging wall collapse.
• "Hanging wall cutoff": The line where a fault intersects the upper surface of a rock layer.
  • The map clearly shows the hanging wall cutoff of the sandstone unit.

Variants and Related Words

• Footwall (n): The mass of rock that lies below an inclined fault plane.
  • The ore deposit was located in the footwall of the shear zone.
• Fault block (n): A section of crust bounded by faults.
• Dip-slip fault (n): A type of fault where movement is primarily parallel to the dip (inclination) of the fault plane; the terms "hanging wall" and "footwall" are most relevant here.

Synonyms

• Upper block (in the context of a dip-slip fault).
• Overlying wall.

Notes

• The concept is crucial for understanding fault mechanics, earthquake genesis, and mineral exploration. In a normal fault, the hanging wall moves down relative to the footwall. In a reverse fault, the hanging wall moves up.

Noun

1. the upper wall of an inclined fault