[CIG-SEISMO] [Specfem3D Cartesian]- Using a CMTSOLUTION source to trigger a critically-stressed fault

[Kangchen Bai]

Hi Ge,

Triggering a dynamic rupture with a point source is do-able with the code.
You should see dynamic stress changes as the wave goes across the fault.
 I actually did similar things before by mistake --- I forgot to turn off
the point source when doing a dynamic rupture simulation and see the
circular stress pattern on the fault.

We also did the work of one fault rupture triggering another using the code
(See Bai & Ampuero 2017
https://doi.org/10.1002/2017JB014848
 ), the stress transfer is not a problem as is shown in Fig 6 & 7.

If you do not see stress changes, there must be something wrong with the
settings.
I suspect the most plausible scenario is that the fault node is not split
in which case the stress remain constant anyhow.
Let me know if you have more questions.

Best,
Kangchen

On Mon, Apr 9, 2018 at 7:21 AM, Dimitri Komatitsch <
komatitsch at lma.cnrs-mrs.fr> wrote:

>
> Dear Ge Li,
>
> Thank you very much for your email and for your interest in the work of
> the community around the package.
>
> Yes, if you want to mimic an extended source using a kinematic source
> model, you can use many CMTSOLUTION sources that are triggered at different
> times and at slightly different locations (see e.g. the discussion about
> extended sources around equation (A12) of http://komatitsch.free.fr/prep
> rints/GJI_1999_figure16_error_fixed_equation3_typo_fixed.pdf, and the way
> we mimic a Hamming quasi-plane wave using 1000 such sources in
> http://komatitsch.free.fr/preprints/Ultrasonics_Moysan_2016.pdf figure 5).
>
> If you want a dynamic rupture source model, i.e. something more
> sophisticated, the package can do that based on the great work of Jean-Paul
> Ampuero, Surendra Nadh Somala, Kangchen Bai and other people in the
> community, they can give you more details (they will know much more about
> this than I do :-)
> Let me thus cc them.
>
> Best regards,
> Dimitri.
>
> On 04/05/2018 03:00 AM, Ge Li wrote:
>
>> To Whom It May Concern:
>>
>> I’m a PhD Candidate in geophysics at McGill University. Currently I’m
>> using
>>
>> Specfem3D Cartesian for my research.
>>
>> I’m wondering is it possible to trigger an earthquake on a fault using a
>> CMTSOLUTION source?
>>
>> I tried several simulations by setting a critically stressed fault and a
>> CMTSOLUTION point source.
>>
>> The source (Mw~6 Right-lateral strike slip) was located about only 1km
>> away from the fault surface.
>>
>> But it turned out the stresses on the fault surface(dynamic
>> slip-weakening) remain unchanged.
>>
>> Based on these tests, I supposed that a CMTSOLUTION won’t change the
>> stress level on a fault surface. Is it correct?
>>
>> Or did I miss something here?
>>
>> Thanks! I’m looking forward to your reply!
>>
>> --
>>
>> *Ge Li*
>>
>> /Ph.D. Candidate/
>>
>> /Department of Earth & Planetary Science, /
>>
>> /McGill University/
>>
>> /3450 University Street/
>>
>> /Montreal, QC, Canada /
>>
>> /H3A 0E8/
>>
>> /ge.li2 at mail.mcgill.ca <mailto:ge.li2 at mail.mcgill.ca>/
>>
>>
>>
>> _______________________________________________
>> CIG-SEISMO mailing list
>> CIG-SEISMO at geodynamics.org
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>>
>>
> --
> Dimitri Komatitsch, CNRS Research Director (DR CNRS)
> Laboratory of Mechanics and Acoustics, Marseille, France
> http://komatitsch.free.fr
>
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