[CIG-SHORT] a PyLith question

[Eunseo Choi]

Hi, Charles,

As for strain weakening, I though I saw it discussed in the manual but 
it was slip-weakening friction on fault.
I'll try plasticity and update you on the results.
Thanks a lot for your help.

Cheers,
Eunseo


On 03/29/11 14:37, Charles Williams wrote:
> Hi Eunseo,
>
> I'm glad it worked.  I'm including cig-short on this because this is 
> the sort of question that could be useful for everyone.  Strain 
> weakening might also be useful, but I haven't put that into the 
> plasticity model yet.  It's been on my list for a while, but the 
> Christchurch earthquake has kept me busy recently.  If you try putting 
> in plasticity, I will be interested to hear what happens.
>
> Charles
>
>
> On 30/03/2011, at 3:34 AM, Eunseo Choi wrote:
>
>> Hi, Charles,
>>
>> It worked! After the line of shared nodes was removed, the 
>> calculation went through and the displacement solution is pretty much 
>> as expected.
>>
>> However, stress field is dominated by that around the gap between two 
>> faults. Displacements also seem affected there.
>> Although not completely sure to what degree this is artificial, I 
>> guess this is why you suggested to have a weak region or plasticity.
>> If plasticity is added in for the purpose of reducing the effect of 
>> fault gap, would it be better to have strain weakening, too?
>>
>> Eunseo
>>
>>
>> On 03/28/11 14:18, Charles Williams wrote:
>>> Hi Eunseo,
>>>
>>> It's good to hear from you.  Unfortunately, when we were first 
>>> designing PyLith, we realized that intersecting faults was a major 
>>> problem.  There were problems with splitting such faults into 
>>> cohesive cells in a consistent way, and also deciding how fault slip 
>>> should be allocated in such a situation.  The simplest solution was 
>>> simply not to allow intersecting faults.  For most problems, this 
>>> isn't an issue.  I can't remember for sure, but I believe that a 
>>> cell can have vertices on more than one fault, but a single vertex 
>>> cannot lie on more than one fault.  In some cases you may want to 
>>> include a weaker region (or maybe plasticity) in the region between 
>>> the two faults.
>>>
>>> With a brief glance, your .cfg file looks OK; however, I suspect 
>>> your problems are due to faults sharing a vertex.  As a test, try 
>>> eliminating the line of nodes shared by both faults from one of the 
>>> faults and see what happens.
>>>
>>> I hope this answers your question, and I hope this doesn't cause 
>>> problems in your modeling.  What sort of problem are you trying to 
>>> solve?
>>>
>>> Cheers,
>>> Charles
>>>
>>>
>>> On 29/03/2011, at 7:06 AM, Eunseo Choi wrote:
>>>
>>>> Dear Charles,
>>>>
>>>> I hope everything is going well with you.
>>>>
>>>> I am trying to see if PyLith can handle stray faults.
>>>> For instance, a fault system composed of a major strike-slip fault 
>>>> and a branching one (fault1+fault2 as in the attached figures).
>>>>
>>>> Using Cubit, setting up the geometry I want was straightforward but 
>>>> the generated mesh appears to be incompatible with the assumptions 
>>>> made by PyLith. The complaint from PyLith was "Invalid orientation 
>>>> in fault mesh".
>>>>
>>>> I wonder if there was any missing step specific to creating a mesh 
>>>> with fault planes intersecting each other; also if it is correct to 
>>>> list two faults as in the attached input file.
>>>>
>>>> Please just let me know if you need more information.
>>>> Thanks.
>>>>
>>>> Best regards,
>>>> Eunseo
>>>>
>>>> -- 
>>>> =====================================
>>>> Eunseo Choi
>>>> Post-Doctoral Research Scientist
>>>>
>>>> Lamont-Doherty Earth Observatory
>>>> 305c Oceanography
>>>> P.O. Box 1000
>>>> 61 Rt. 9W
>>>> Palisades, NY 10964-8000
>>>>
>>>> http://www.ldeo.columbia.edu/~echoi 
>>>> <http://www.ldeo.columbia.edu/%7Eechoi>
>>>> Phone: 845-365-8813 Fax: 845-365-8156
>>>> =====================================
>>>>
>>>> <Halfsine_Vertical_Splay.cfg><fault1.png><fault2.png>
>>>
>>> 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 <mailto:C.Williams at gns.cri.nz>
>>>
>>> Notice: This email and any attachments are confidential. If received 
>>> in error please destroy and immediately notify us. Do not copy or 
>>> disclose the contents.
>>>
>>>
>>
>>
>> -- 
>> =====================================
>> Eunseo Choi
>> Post-Doctoral Research Scientist
>>
>> Lamont-Doherty Earth Observatory
>> 305C Oceanography
>> P.O. Box 1000
>> 61 Rt. 9W
>> Palisades, NY 10964-8000
>>
>> http://www.ldeo.columbia.edu/~echoi
>> Phone: 845-365-8813 Fax: 845-365-8156
>> =====================================
>
> 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 <mailto:C.Williams at gns.cri.nz>
>


-- 
=====================================
Eunseo Choi
Post-Doctoral Research Scientist

Lamont-Doherty Earth Observatory
305C Oceanography
P.O. Box 1000
61 Rt. 9W
Palisades, NY 10964-8000

http://www.ldeo.columbia.edu/~echoi
Phone: 845-365-8813 Fax: 845-365-8156
=====================================

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