normal fault

Thân thiện

A diagram shows a normal fault in a cross-section of rock layers.

Definition

Noun: * A type of geological fault: A "normal fault" is a specific kind of inclined fracture in the Earth's crust. It is characterized by the block of rock above the fault plane (the hanging wall) moving down relative to the block below the fault plane (the footwall). This movement typically occurs due to extensional tectonic forces that pull the crust apart.

Usage

• "Normal fault" is a technical term used primarily in geology, seismology, and earth sciences.
• It describes both the structural feature and the specific sense of slip (downward movement of the hanging wall).
• It is often contrasted with a "reverse fault" or "thrust fault," where the hanging wall moves upward.

Examples

• The Basin and Range Province in the western United States is characterized by numerous normal faults created by crustal extension.
• Geologists identified the earthquake's origin as a normal fault deep within the rift valley.
• In the cross-section diagram, you can clearly see the normal fault where the hanging wall has dropped down.

Advanced Usage

• "Listric normal fault": A normal fault whose plane is curved, becoming flatter with depth.
• The term is used in tectonic analysis: "The region is undergoing normal faulting," indicating the dominant type of crustal deformation is extension.

Variants and Related Words

• Normal faulting (n): The process or occurrence of forming normal faults.
• Extensional fault (n): A synonym often used in tectonic contexts.
• Graben (n): A depressed block of land bordered by parallel normal faults.
• Horst (n): A raised block of land bordered by parallel normal faults.

Synonyms

• Extensional fault
• Gravity fault (an older, less common term)

Antonyms

• Reverse fault
• Thrust fault

Học thuật

Noun

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

Từ đồng nghĩa

• gravity fault
• common fault