[CIG-SHORT] Fault direction in 3D fault

[Charles Williams]

Hi Jiangzhi,

Did you make any more progress on this?  Were the strike_dir, dip_dir, etc., consistent with what you thought?  These are just direction cosines, so you can plot them as vectors to see what they look like.

Also, I noticed that you only specified up_dir for one of your faults.  I believe that the default is [0,0,1], but it’s probably a good idea to specify this as well for consistency.

Cheers,
Charles


On 3/05/2014, at 8:03 am, Jiangzhi Chen <jzchenjzarthur at gmail.com> wrote:

> Hi Brad and Charles,
> 
>    Thanks for your advice. First I tried Brad's suggestion, but the slab still went to wrong direction (screen1 and screen2). To be clear, the model simulates the Cascadia subduction zone, X is easting, Y is northing, and Z is up. Currently I have slabtop and slabbot both creeping at 8 cm/yr, and the slab is supposed to go down with slight rotation because of the geometry of the subduction boundary.
> 
>    Then I tried the suggestion from Charles, changed the bc_dof on the side to 1, and bc_dof on the bottom to 2, with up_dir [0,0,1]. This time, the slab did go down, but it just sank all way down (slab.gif).
> 
> Jiangzhi
> 
> On 05/01/2014 04:53 PM, Brad Aagaard wrote:
>> Jiangzhi,
>> 
>> If this is the same model you used a while ago, then I believe you use [0,1,0] as the up_dir for the domain. You need to set the up_dir to [0,1,0] for all faults and boundaries.
>> 
>> You should request that the fault orientation be information be written so that you can see the strike_dir, dip_dir, and fault normal directions for your geometry. This will help you debug the fault slip directions. See examples/3d/hex8/step06.cfg for how to request the fault directions be output.
>> 
>> Brad
>> 
>> 
>> On 5/1/14, 4:25 PM, Charles Williams wrote:
>>> Hi Jiangzhi,
>>> 
>>> One problem that I see is that I think you’ve mixed up the bc_dof for your bottom boundary (should be 2) compared to your front and back boundaries (should be 1).  Let me know if this helps.
>>> 
>>> Cheers,
>>> Charles
>>> 
>>> 
>>> On 2/05/2014, at 10:26 am, Jiangzhi Chen <jzchenjzarthur at gmail.com> wrote:
>>> 
>>>> Hi everyone,
>>>> 
>>>>    I have a 3D subduction model simulating the interseismic deformation, where I have both fault_slabtop and fault_slabbot creeping. I have set fault_slabtop with reverse_slip of 8 cm/yr and fault_slabbot with reverse_slip of -8 cm/yr, and used the up_dir parameter [0,0,1], but still the subduction is in wrong direction. I am not sure what is wrong. The configuration files are attached. Thanks.
>>>> 
>>>> Jiangzhi
>>>> <screen.png><pylithapp.cfg><interseismic.cfg><mat_conmantle.spatialdb><mat_oceanlitho.spatialdb><mat_oceanmantle.spatialdb><mat_conlitho.spatialdb>_______________________________________________ 
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>>> 
>>> 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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>> 
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> 
> <screen1.png><screen2.png><slab.gif>_______________________________________________
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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