[CIG-SHORT] Fault direction in 3D fault

[Jiangzhi Chen]

Thanks for your advice, I am still trying to get the slab move correctly. The part I am confused is that the slab just sinks down, as shown in the gif figure in my previous email. Is this up_dir related to the fault type, i.e., reverse fault or normal fault? In my case, the slab top is a reverse fault, and slabbot is a normal fault. Maybe the reason is that I did not specify up_dir for the slabbot fault.

Jiangzhi

On May 4, 2014, at 2:20 PM, Charles Williams <willic3 at gmail.com> wrote:

> 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>_______________________________________________ 
>>>>> CIG-SHORT mailing list
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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>_______________________________________________
>> CIG-SHORT mailing list
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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
> 
> _______________________________________________
> CIG-SHORT mailing list
> CIG-SHORT at geodynamics.org
> http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-short