Definition

1. Noun:
   • A type of geological fault: A "common fault" is a specific kind of inclined fracture in the Earth's crust where the rock mass above the fault plane (the hanging wall) has moved downward relative to the rock mass below (the footwall). This downward movement is caused by extensional tectonic forces.

Usage

• Noun:
  • Geologists identified a large common fault in the region, indicating significant crustal extension.
  • The valley was formed by the activity of a common fault over millions of years.

Advanced Usage

• "to be bounded by a common fault": Describes an area whose limit is defined by this type of fault.
  • The graben is bounded by a common fault on its eastern side.

Variants and Related Words

• Normal fault: This is the standard and more frequently used synonym for "common fault" in geology.
• Gravity fault: An older, less common term with the same meaning.
• Extensional fault: A broader term that includes "common fault" as a specific type.

Synonyms

• Normal fault: The primary and most precise synonym.
• Tensional fault: Highlights the causative force (tension).

Antonyms

• Reverse fault / Thrust fault: Fault types where the hanging wall moves upward relative to the footwall, caused by compressional forces.

Related Phrases

• Fault plane: The surface along which the movement occurs.
• Hanging wall: The block of rock that lies above an inclined fault plane.
• Footwall: The block of rock that lies below an inclined fault plane.
• Dip-slip fault: A category of faults where movement is primarily vertical along the dip of the fault plane; a common fault is a type of dip-slip fault.

Noun

1. an inclined fault in which the hanging wall appears to have slipped downward relative to the footwall