# Questions of fault parameters

**URL:** <https://community.geodynamics.org/t/questions-of-fault-parameters/2144>\
**Category:** PyLith\
**Created:** [December 26, 2021, 2:02pm UTC](https://community.geodynamics.org/t/questions-of-fault-parameters/2144 "2021-12-26T14:02:40Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![luxiaokong](https://avatars.discourse-cdn.com/v4/letter/l/3d9bf3/32.png) [@luxiaokong](https://community.geodynamics.org/u/luxiaokong)\
**Post date:** [December 26, 2021, 2:02pm UTC](https://community.geodynamics.org/t/questions-of-fault-parameters/2144/1 "2021-12-26T14:02:40Z")

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Dear Pylith team,

We specifies fault parameters in terms of lateral motion, reverse motion, and fault opening as shown in Figure 1.

 ![image](https://canada1.discourse-cdn.com/flex036/uploads/geodynamics/original/1X/070740beaccc7b0b45172e4e989591700b3e6a87.png)

I have observed the fault results of the output file of examples/3d/hex8/step03.cfg. The slip in the x direction corresponds to the left-lateral-slip and the slip in the y direction corresponds to the reverse-slip as shown in figure 2 and 3.

 ![2021-12-26 19-56-43 的屏幕截图](https://canada1.discourse-cdn.com/flex036/uploads/geodynamics/original/1X/03029a642d37853368542637ecce1452cc9fd493.png)

 ![2021-12-26 19-58-07 的屏幕截图](https://canada1.discourse-cdn.com/flex036/uploads/geodynamics/original/1X/5447484e9994d5063b769eff0a4af362e6f0f0e8.png)

This appears to be a mismatch with the direction specified in Figure I. I think that the left-lateral-slip should correspond to y direction and the reverse-slip should be z direction.Is there something wrong with my understanding?  
Thank you in advance.

Nick

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**Author:** ![baagaard](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/baagaard/32/615_2.png) [@baagaard](https://community.geodynamics.org/u/baagaard)\
**Post date:** [December 27, 2021, 2:51am UTC](https://community.geodynamics.org/t/questions-of-fault-parameters/2144/2 "2021-12-27T02:51:09Z")

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ParaView will label the components of any vector as `x`, `y`, and `z`. In the case of slip, the components are actually `left-lateral`, `reverse`, and `fault-opening`.