Talk:Geologic fault

From Academic Kids

When I visited the webpage http://www.wikipedia.org/wiki/Geologic_fault, I was very glad that I had finally found a webpage on faults, but I was really confused by the language. Something that a long-ago English teacher once said to me: When you answer an essay question, tell all the facts you know, make the answer as complete as possible. Then say what that means. ex. "The Earth is an oblate sphere. THIS MEANS that the Earth is a sphere, but because of the fact that it spins on an axis, centripical force flattens the poles and pushes out the center. A good way for you and I to understand what this means is by thinking of a popular toy much like a yo-yo. This toy is a, viscous disk about 1 cm thick and 4cm in diameter. It is attached to two strings coming out of either side. One twists these strings, then untwists them with a flick of the wrists, repeating this motion until the circle blurs, appearing bigger than it is. In truth, it is not an illusion, but that the centripical force has pulled the edges of the disk out with material taken from the top and bottom of the disk, forcing it to squish in. This is how the Earth acts." I am not saying that the explanation of each fact should be as complete as this one– no, for that much information would be much too much. However, in the way that this explanation makes you understand (or at least tries to), you don't have to be comfortable with scientific language. If you understand the part quoted about the toy, you don't even have to be able to think abstractly. I think that your geography page could do well to be written in some way more similar to this.

It's a geology page, rather than a geography page, but fair point. Will have another crack at it. charlieF

Hangingwall/Footwall

I am (was) trying to learn about terminology of structural geology. I found this web page and read it, and thought I understood it. Then I visited another site, the Schlumberger oilfield services oilfield glossary page about faults. I thought I understood what a hanging wall was from this page since I could grasp the concept of 'the block above the fault' easily. What I mean is that I had an 'intuitive' feeling for the concept of a fault plane (as long as it wasn't vertical) and could easily grasp the idea of the block above this plane and the one below it. Then I went back to this page and realised that according to the Schlumberger definition what is called the hanging wall here I would call the footwall and vice versa. I don't understand why. Don't forget I'm an amateur and could be missing something obvious.

I'm pretty sure the caption on the picture is backwards and the Schlumberger source is correct. Can anyone think of a quick fix? -- Walt Pohl 16:56, 17 Mar 2004 (UTC)

I agree. I can't find a web page that agrees with our picture, so I swapped the labels. -- Heron 21:24, 17 Jul 2004 (UTC)

integration

Text copied from newly created article 'Faults'. Maybe there is something that ought to be integrated into the article:

A fault is a fracture in the crust of the earth that has caused displacement (offset) of the crust. Faults may offset soil or rock materials on either side of the fault plane for distances ranging from less than a few inches to distances on the order of hundreds of miles. Faults are usually associated with past or present tectonic movement, seismic activity (earthquakes), and volcanic activity. Faults may be quite old features (having displaced rocks millions of years old) to recent features that have displacement rocks within historic times. Faults may be too old since their last displacement to be of concern to man, whereas recently active faults, particularly those faults associated with recent large earthquakes, can be a significant hazard to man.

- snoyes 11:35, 5 Jul 2004 (UTC)

Reverse fault same as thrust fault?

Some texts, unlike our article, make a distinction between reverse fault and a thrust fault. A reverse fault is the exact opposite of a normal fault, while a thrust fault is the slippage of two strata past each other under horizontal compression. Is this distinction generally accepted? -- Heron 21:40, 17 Jul 2004 (UTC)

Thrust faults and Reverse faults are the same thing (Glossary of Geology) User:Dushan Jugum

Many structural geologists would use "thrust fault" for a compressive fault dipping LESS than 45 degrees and "reversed fault" for a compressive fault dipping MORE than 45 degrees. User:Denbrok