For the tangent-linear ion diagrams, I originally chose to plot the slip direction of the footwall block because that convention results in consistency with the long-standing convention for strike-slip faults that the slip sense (right or left lateral) is determined by the relative motion of the fault block on the opposite side of the fault from the observer.  With the Hoeppener convention, one ends up with a right-lateral fault having a tangent-lineation arrow pointing to the left relative to the center of the stereonet. 
  Rob Twiss


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On 27 Jul 2015, at 08:16, Kamil Ustaszewski <[log in to unmask]> wrote:

Dear Andrea,

Damien Delvaux's Wintensor software is able to produce "Twiss-type" tangent lineation diagrams:

http://www.damiendelvaux.be/Tensor/WinTensor/win-tensor.html

Remember that Twiss' tangent lineation diagrams portray the relative slip sense of the footwall fault block.
A variation of the tangent lineation diagram sensu Twiss was developed by R. Hoeppener in the 1950ies in Germany*. In contrast to the "Twiss method", Hoeppener plotted the movement direction of the hanging wall block.

TectonicsFP (http://tectonicsfp.com) allows you to plot fault-striae pairs and switch quickly between "Angelier plots" (i.e., fault-slip pair shown as a great circle with its fault striae) and the Hoeppener tangent lineation (showing the motion of the hangingwall block). I personally prefer Hoeppener-type diagrams over Twiss' tangent lineation diagrams, because they are consistent with "Angelier-type" diagrams in the sense that they both portray the relative motion of the hangingwall fault block.

Best wishes,
Kamil


*) Hoeppener, R. (1955), Tektonik im Schiefergebirge, Geologische Rundschau, 44(1), 26-58.



______________________________________
Kamil Ustaszewski
Head of Structural Geology
Institute of Geological Sciences
Friedrich-Schiller University Jena
______________________________________
Tel. +49(0)3641-948623
Burgweg 11 — office H106
D-07749 Jena, Germany





On Jul 27, 2015, at 13:42 , Andrea Billi <[log in to unmask]> wrote:

Dear All,

do you know where I can find a software able to produce tangent lineation diagrams (Twiss and Moores, Structural Geology 2nd ed., 2007, page 437)?

thanks a lot
Andrea

_________________________________________________
Andrea Billi (PhD)
Consiglio Nazionale delle Ricerche, IGAG,
c.o. Dipartimento Scienze della Terra,
Sapienza Università di Roma,
P.le A. Moro 5, 00185, Rome, Italy.

Phone: +39 06-49914955
Skype: a.billi
Email: [log in to unmask]
Web site: http://www.andreabilli.com
Photos: https://www.flickr.com/photos/andreabilli68/
_________________________________________________

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