[CIG-SEISMO] integrated inversion tool for SPECFEM3D (will be released before the summer)

[emanuele casarotti]

You should consider pycmt3d https://github.com/wjlei1990/pycmt3d

Il giorno lun 19 giu 2017 alle 19:48 Dimitri Komatitsch <
komatitsch at lma.cnrs-mrs.fr> ha scritto:

>
> Hi Surendra, Hi all,
>
> Vadim's tool currently inverts for the model only, mostly because we
> developed it for oil industry problems, in which case the location of
> the active source is known. Here is what SPECFEM3D users classically do
> to relocate earthquake sources (paragraph taken from a text written by
> Federica Magnoni and Emanuele Casarotti for Italy):
>
> "As initial source parameters of the chosen events we use Time Domain
> Moment Tensor solutions (TDMT, Dreger and Helmberger, 1993; Scognamiglio
> et al. 2009) that are calculated by inverting full three-component
> traces of regional broad-band stations using 1D wave speed models.
> Before starting the tomographic inversion, we then exploit the initial
> 3D model of Italy of Di Stefano and Ciaccio (2014) to recalculate the
> source parameters of the considered events. The TDMT solutions, based on
> 1D wave speed models, are considered as initial solutions and we invert
> for the six moment tensor components and the event location by using the
> technique presented in Liu et al. (2004). We use SPECFEM3D to
> numerically calculate the Fréchet derivatives with respect to the source
> parameters based on 3D models and we minimize a waveform misfit function
> to invert for source solutions. If the variance reduction of the
> solution with the 3D model is significant, this is considered as the new
> moment tensor solution of the event."
>
> which comes from this paper by Qinya Liu:
> http://komatitsch.free.fr/preprints/bssa_Qinya_inversion_2004.pdf and in
> which the derivatives are computed using finite-differences.
>
> Emanuele and Federica (and Qinya), do you have scripts to do that?
> if so, are they in the package somewhere (or should we consider
> committing them?); that would be very useful.
>
> Thanks,
> Best regards,
> Dimitri.
>
> On 06/06/2017 06:31 PM, Surendra Nadh Somala wrote:
> > Dear Dimitri,
> >
> > Are these tomographic inversions or can SPECFEM3D also be used for
> > source inversions?
> >
> > Thanks,
> > Surendra
> >
> >
> > ___________
> > *Surendra Nadh Somala*
> > Assistant Professor
> > Department of Civil Engineering (Block-E, 208)
> > Indian Institute of Technology (IIT) Hyderabad
> > Kandi, Sangareddy
> > Telangana, India - 502285
> > Phone : +91 (0)40 2301-8457
> > http://www.iith.ac.in/~surendra/
> >
> > On Tue, Jun 6, 2017 at 9:56 PM, Dimitri Komatitsch
> > <komatitsch at lma.cnrs-mrs.fr <mailto:komatitsch at lma.cnrs-mrs.fr>> wrote:
> >
> >
> >     Hi all,
> >
> >     Vadim Monteiller here in our group has created a nice integrated FWI
> >     tool for SPECFEM3D (based on L-BFGS and following
> >     http://komatitsch.free.fr/preprints/GJI2_Vadim_2015.pdf
> >     <http://komatitsch.free.fr/preprints/GJI2_Vadim_2015.pdf> Sections 3
> >     and 4). The advantage is that it uses no I/Os to disk, all the
> >     inversion routines (computing sensitivity kernels, smoothing them,
> >     summing, iterating) are called from a single (parallel) calling
> >     program and thus only memory is used.
> >     We have designed a set of examples, which we will put in BuildBot.
> >
> >     We will release it before the summer, Vadim is finishing a few final
> >     tests.
> >
> >     Best regards,
> >     Dimitri.
> >
> >     --
> >     Dimitri Komatitsch, CNRS Research Director (DR CNRS)
> >     Laboratory of Mechanics and Acoustics, Marseille, France
> >     http://komatitsch.free.fr
> >     _______________________________________________
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> >
> >
> >
> >
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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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