Editing 1874: Geologic Faults

{{comic
| number    = 1874
| date      = August 9, 2017
| title     = Geologic Faults
| image     = geologic_faults.png
| titletext = I live on a torn-bag-of-potato-chips-where-the-tear-is-rapidly-growing fault, which is terrifying.
}}

==Explanation==

This comic appears to be a successor to [[1714: Volcano Types]]. Similar to its predecessor, the comic explores several phenomena (in this case, geologic faults), both real, and several made up for the point of a joke.

A {{w|Fault (geology)|fault}} is a geologic feature involving a planar fracture with displacement in a large mass of rock, including the boundaries of two {{w|tectonic plates}}.

====Real geologic faults====
;Normal fault
In a {{w|Fault (geology)#Dip-slip faults|normal fault}}, the hanging wall (the lower wall; right) moves downward relative to the footwall (the upper wall; left). The Earth's crust is extended in this type of fault. 
;Reverse fault
A reverse fault is basically the opposite of a normal fault. The hanging wall (left) moves upward relative to the footwall (right), and the Earth's crust is compressed.
;Transverse fault
A transverse fault, also known as a {{w|transform fault}}, is where the two plates move parallel to each other, but in opposite directions.
;Thrust fault
A {{w|thrust fault}} is when older rocks are pushed (or thrust) on top of younger rocks. The angles are typically lower (more horizontal) than in reverse faults.

====Fictional joke faults====
;Taffy fault
This appears to involve one tectonic plate, that is being stretched out like a piece of {{w|Taffy (candy)|taffy}}.  [https://s3.amazonaws.com/academia.edu.documents/41229455/Crustal_thinning_recorded_by_the_shape_o20160113-25699-1vca65l.pdf20160115-19908-17j9qxl.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1502469630&Signature=hcKl8ViPa2JrofM%2Bob7qu9TmjP4%3D&response-content-disposition=inline%3B%20filename%3DCrustal_thinning_recorded_by_the_shape_o.pdf Ductile crustal thinning] of this type actually occurs in rocks under tension at {{w|Brittle–ductile_transition_zone|sufficient depths}}.  Such deformation is not a fault, however, as there is no fracture along which movement takes place.
;Splinted fault
This appears to be a normal or reverse fault that someone has attempted to fix in position by attaching a large splint, as you might with a broken bone. This is unlikely to prove effective{{Citation needed}}.
;Squeezed-bar-of-soap fault
Two plates seem to be moving towards each other, while a third smaller plate is squeezed between them and pushed upwards, much as a slippery bar of soap might pop up when squeezed between two hands.
;Apple power cable fault
The plate appears to have been twisted and bent so many times that parts of it are fraying and the end is splitting apart, similar to a damaged Apple {{w|MagSafe}} connector.
;Brio fault
{{w|Brio (company)|BRIO}} is a company from Sweden that makes wooden toys, including train sets. The Brio fault seems to be two tectonic plates which join together like the Brio train track pieces do. (However, this join is obvously incorrect because of the height difference.)
;Torn-bag-of-potato-chips-where-the-tear-is-rapidly-growing fault
The title text refers to when a bag of chips gets a tear in it. When this happens, any further stress on the bag, such as reaching in to get more chips, can easily increase the size of the tear, sometimes very quickly. It would be frightening to live near a fault that behaved like this{{Citation needed}} because it could cause major seismic events very quickly. If you were close enough to the fault, you might be afraid that the crack would grow underneath you, causing you to fall into the bag of chips — or, rather, the Earth.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon. Lacks small description for each item.}}
:[The comic shows nine different schematic views to present geographic faults and some more.]

:[Two planes with a slip fault drifting away to the left and right.]
:Normal fault
:[Two planes with a slip fault drifting against each other from left and right.]
:Reverse fault
:[Two planes moving sideways.]
:Transverse fault

:[The left plate is moving over the right plate, while the right plate is sliding under the left one]
:Thrust fault
:[Two planes drifting away and the connection between them gets smaller, like a piece of taffy candy.]
:Taffy fault
:[On top of both planes a small piece with splints holds them together.]
:Splinted fault

:[The two planes pressing together with a piece in the middle moving upwards.]
:Squeezed-bar-of-soap fault
:[The right plane is connected to the left and swinging up and down.]
:Apple power cable fault
:[One side with a thin connector and the other with an evenly spaced hole connecting the planes together. The pieces fit together like a puzzle.]
:Brio fault

==Trivia==
Faults have been mentioned several times in xkcd. Thrust faults were previously mentioned in [[1082: Geology]], and in the title text of [[1388: Subduction License]], [[Beret Guy]] tells [[Cueball]] he can't be a 'normal' roomate because in his motion he is creating a reverse fault.

A similar joke to the Apple power cable fault is used in [[1406: Universal Converter Box]].

{{comic discussion}}

[[Category:Science]]
[[Category:Puns]]