[CIG-SHORT] fault traction orientation

[Birendra jha]

Hi Charles

I agree with positive tractionZ denoting tension.
But isn't the updip direction determined by the "dip_dir" vector? So for the fault in picture, which has the given dip_dir vector, isn't positive tractionY pointing downdip? What is the purpose of dip_dir vector?

Thanks
Birendra 
--------------------------------------------
On Wed, 6/17/15, Charles Williams <willic3 at gmail.com> wrote:

 Subject: Re: [CIG-SHORT] fault traction orientation
 To: cig-short at geodynamics.org
 Date: Wednesday, June 17, 2015, 3:58 PM
 
 Hi Birendra,
 
 I’m fairly sure that
 positive traction y should mean updip shear, and positive
 traction z should be tension.  Similarly, positive traction
 x should be left-lateral shear.  Unfortunately, I don’t
 think we have a 3D example that demonstrates this, but you
 could put one together by putting in a dipping fault with no
 slip.  You can then apply BC that should give updip shear,
 and another set of BC to produce tension.  Look at the
 resulting fault stresses and see if this agrees with what I
 said.  Let us know if this works for you.
 
 Cheers,
 Charles
 
 
 >
 On 17/06/2015, at 2:29 am, Birendra jha <bjha7333 at yahoo.com>
 wrote:
 > 
 > Hi
 > 
 > I have questions on
 pylith fault traction orientations. Please open the attached
 figure. I loaded the fault info.vtk file in paraview to find
 out normal_dir and dip_dir directions. These vectors are in
 global coord system as per manual. For the fault in the
 picture, can you please answer those questions?
 > 
 > Thanks a
 lot
 >
 Birendra<fault_tractions.png>_______________________________________________
 > CIG-SHORT mailing list
 > CIG-SHORT at geodynamics.org
 > http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-short
 
 Charles A. Williams
 Scientist
 GNS Science
 1 Fairway Drive, Avalon
 PO Box
 30368
 Lower Hutt  5040
 New
 Zealand
 ph (office): 0064-4570-4566
 fax (office): 0064-4570-4600
 C.Williams at gns.cri.nz
 
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