Talk:Extensional fault

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Everything in the article is relevant to the topic of extensional fault. It explains the definition of the concept and examples of occurrences. The description about stress field and ground layer later in the paragraph is harder to follow comparing to the introductory sentences. All the information is up to date since the reference was published in 2002 and revised in 2009. More information about how extensional fault formation could be added and explained in details. The article could be improved by adding more references and providing details. The scientific information like the angles are presented clearly and accurately. The article links to other Wikipedia articles like "Extensional tectonics" which describes the outcomes of the structures associated with stretching of planetary body's crust and "Graben" which describes a depressed block of the crust of a planet. The article is written in a neutral tone. There is no evidence or sentences that appear heavily biased toward any particular position. There are no viewpoints in the article. But it would be helpful to describe different opinions on the topic. Overall, the paragraph does a great job at connecting with other related topics in terms of content. Ywangg (talk) 23:08, 15 October 2021 (UTC)

Wiki Education Foundation-supported course assignment

This article was the subject of a Wiki Education Foundation-supported course assignment, between 23 August 2021 and 7 December 2021. Further details are available on the course page. Student editor(s): Ywangg. Peer reviewers: ProudPlantParent.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 21:03, 16 January 2022 (UTC)

Needs some plain English

I took a semester of geology in college a long time ago, and I've retained a mild-to-moderate interest in geology ever since. I claim no expertise at all. I have read this very short article about ten times and also looked at the linked pages for better understanding of the terminology contained herein. I can honestly say that I still have only a faint concept of what this article is trying to describe; I remain unable to visualize the phenomenon. (Edit: I did not focus enough on the upper photo; it certainly helps.) Here are some of the phrases and terms that are not clear to me: "vertically thins"; "may be rotated"; "a shallower geometry"; "generally planar"; "orthogonal to the Earth's surface"; "a dip." I probably should have known that "orthogonal" is defined as "perpendicular," and a little online research enabled me to understand that "dip" is very standard geological terminology. The second part of the final sentence (from "so long as" to "seismogenic layer") is not clear. Likely, there should be a comma after the word "surface." After reading some online geology articles, I have copyedited and further wikified the article to provide better clarity. The meaning of "vertically thins," which seems vital to understanding the phenomenon described by this article, is unclear; possibly it means "reduces the thickness of the crust." I copyedited the last sentence to extract meaning from the phrase about "initiate," which I believe is intended to refer to slippage along the fault. Hopefully, a knowledgeable editor can confirm that's correct and also comment on the accuracy of my belief that "vertically thins" refers to crust "thickness." If so, a little more copyediting can provide even more clarity. DonFB (talk) 12:36, 30 December 2016 (UTC)

Thanks, this was an early effort of mine and was written too much for the specialist reader. I'll think on how to improve this further, hopefully with your help. Mikenorton (talk) 18:42, 30 December 2016 (UTC)

Appreciate your response. I can easily grasp the idea of "steeply-dipping fault blocks," but "low angle" seems to contradict "steeply-dipping"; low angle in relation to what? I also can't quite see what "rotate" means. Does it mean the faults and blocks are becoming more horizontal (or vertical)? Perhaps the text could say "rotate so the faults and blocks become more horizontal/vertical (whichever is correct). I also have second thoughts about my own suggestion of "reduces the thickness." Does the crust between the surface and mantle actually become thinner? Or does the phrase refer to the "thinness" or "thickness" of the fault blocks themselves? DonFB (talk) 21:08, 30 December 2016 (UTC)

Actually they rotate together in the same sense, preserving the angle between any initially planar marker such as horizontal bedding and the fault surface - known as the "cut-off angle", although I won't introduce that terminology. Large extensional faults do thin the upper crust, although this can involve the whole of the lithosphere - here's an example that would explain it better I think - File:Tilted Blocks.png. Mikenorton (talk) 22:16, 30 December 2016 (UTC)