fault
FAWLT
fɔːlt
An extended break in a body of rock, marked by the relative displacement and discontinuity of strata on either side of a planar fracture.
In geology, it's a specific type of fracture where there has been movement.
The story behind the word. The geological "fault" shares its origin with the more common meaning of "mistake" or "defect." It comes from the Old French word "faute," meaning "lack" or "failure." In geology, it refers to a "failure" in the Earth's crust – a break where the rock has moved, causing a discontinuity. It's a flaw in the Earth's otherwise continuous structure.
Word relationships
- fracture: A general term for a break in rock, not necessarily with displacement.
- rift: A large crack or split in the Earth's crust, often associated with spreading plates.
Commonly confused with
- fissure: A fissure is a long, narrow crack or opening, but doesn't necessarily imply the displacement of rock blocks that defines a geological fault.
Word family
- faulted (adjective): Having or affected by a fault or faults.
Collocations
- fault line
- active fault
- major fault
- normal fault
- reverse fault
- strike-slip fault
Idioms & expressions
- at fault
- find fault with
- to a fault
Example sentences
- "The San Andreas Fault is a major transform fault responsible for many earthquakes in California." Explaining earthquakes.
- "Geologists identified a previously unknown fault line running beneath the city." Geological survey.
Memory hook
Think of a 'fault' in a computer program, a break where things go wrong. Here, it's a break in the Earth. Earth's break
When not to use
Don't use for a simple crack without displacement. Also, avoid the general meaning of 'mistake' unless context is clear.
Fun facts
- The largest known fault system on Earth is the Mid-Ocean Ridge system, which circles the globe.
Explore more words
Also appears in
Take your vocabulary further with LangBlitz
Our English vocabulary app: FSRS spaced repetition, 5,000+ curated words across 119 topic groups, CEFR A1 to C2. Explore your mastery with the beautiful Vocabulary World feature.