normal fault

American  

[nawr-muhl fawlt] / ˈnɔr məl ˌfɔlt /

noun

Geology.

1. a fault along an inclined plane in which the upper side or hanging wall appears to have moved downward with respect to the lower side or footwall (opposed to reverse fault).

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normal fault Scientific  

1. A geologic fault in which the hanging wall has moved downward relative to the footwall. Normal faults occur where two blocks of rock are pulled apart, as by tension.

2. Compare reverse fault See Note and illustration at fault

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Etymology

Origin of normal fault

First recorded in 1875–80

Example Sentences

At Powhatan High School, where social groups fall along the normal fault lines, students maintain friendships on either side of the political divide.

From Washington Post • Nov. 30, 2019

Half-grabens are a one-sided version of a horst and graben, where blocks are tilted by a normal fault on one side, creating an asymmetrical valley-mountain arrangement.

From Textbooks • Jan. 1, 2017

The basins and ranges referred to in the name are horsts and grabens, formed by normal fault blocks from the crustal extension, as discussed in chapter 2 and chapter 9.

From Textbooks • Jan. 1, 2017

In the Basin and Range Province, the dip of a normal fault tends to decrease with depth, i.e., the fault angle becomes shallower and more horizontal as it goes deeper.

From Textbooks • Jan. 1, 2017

A normal fault with a hade of 15 degrees, the original fault scarp remaining.

From The Elements of Geology by Norton, William Harmon