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fault throw versus length.
http://www.epgeology.com/structural-geology-f21/fault-throw-versus-length-t136.html
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Author:  Jim111 [ Thu Oct 14, 2010 10:28 pm ]
Post subject:  fault throw versus length.

Any relations (out of the top of your head) of fault length vs throw?? Normal faults preferably and in rather unconsolidated shallow sections... Just need quick figures to strengthen my point of view here in my office.

thanks!

Author:  Jameslauwton [ Thu Oct 14, 2010 10:33 pm ]
Post subject:  Re: fault throw versus length.

Jim,

Although I know your looking for quick figures I think this topic needs some indepth explanations..
A large number of studies show that fault through vs length have a linear relationship. This is called the D/L ratio and gives insight in the shear deformation of the micro and macro-scale strucutres that accommodate deformation as a result of stress. Some scientist still debate this simple relationship though.

Anyway... to answer your question I have attached a logarithmic plot of a fault length vs fault displacement of a fault in the North Ses (Pickering et al. 1996) The relationship plots largely along a straight line.

A different study by Schultz and Fossen in 2002 also plotted the same fault parameters Throw vs Length of a variety of sources. The conclusion was that the maximum displacement depends on both the fault length and height as well as the driving stress and several rock properties. There is no such thing as a relationship that is consistent for all lithologies and stress regimes, but comparing faults in a region can give insight in fault Length and throw relationships.

I attached the plot by Schultz et al. 2002 aswell...

The D/L ratio I am talking about here is usually calculated from the displacement profiles (which show the fault length vs height) together with other factors such as rock type and applied stress. Once again, there is no uniform relationship you can apply everywhere over the world.

Hope this helped!

Attachments:
File comment: Schultz and Fossen (2002) plotted the Throw/Length Ratio of various published data sets. It was found that the maximum displacement depends on both the fault length and height in addition to driving stress and rock mass properties (Schultz and Fossen, 2002). A population of Deformation Bands from Fossen and Hesthammer (1997) is also marked in the plot.
schultzfossen2002.jpg
schultzfossen2002.jpg [ 39.24 KiB | Viewed 4247 times ]
File comment: Pickering et al 1996, plotted fault throw/length ratio from faults in the North Sea. They found that the data showed considerable scatter, but if they added a length of 500 m to make up for the fault tips that were below seismic resolution the data more closely fitted a linear relationship.
throwlengthratio.jpg
throwlengthratio.jpg [ 57.82 KiB | Viewed 4247 times ]

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