[CIG-SEISMO] integrated inversion tool for SPECFEM3D (will be released before the summer)
Dimitri Komatitsch
komatitsch at lma.cnrs-mrs.fr
Tue Jun 20 06:40:51 PDT 2017
Hi Federica and Emanuele, Hi all,
Thanks for your answers. Very useful. I am going to cut and paste them
in the manual of SPECFEM and put a copy of cmt3d and of pycmt3d in the
Git version of SPECFEM (they are compatible in terms of license, pycmt3d
is LGPLv3 and SPECFEM is GPLv2+, which makes the combination GPLv3
according to Wikipedia).
best wishes,
Dimitri.
On 06/20/2017 10:54 AM, Federica Magnoni wrote:
> Hi all,
>
> Initially we used the fortran code cmt3d
> (https://github.com/UTCompSeismo/GRD_CMT3D/tree/master/cmt3d) and
> recently, as Emanuele said, we switched to the python code pycmt3d.
>
> Best regards,
> Federica
>
> 2017-06-19 19:53 GMT+02:00 emanuele casarotti
> <emanuele.casarotti at gmail.com <mailto:emanuele.casarotti at gmail.com>>:
>
> You should consider pycmt3d https://github.com/wjlei1990/pycmt3d
> <https://github.com/wjlei1990/pycmt3d>
>
>
> Il giorno lun 19 giu 2017 alle 19:48 Dimitri Komatitsch
> <komatitsch at lma.cnrs-mrs.fr <mailto: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 <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 <tel:+91%2040%202301%208457>
> > http://www.iith.ac.in/~surendra/
> <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>
> <mailto: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>
> > <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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> >
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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
>
>
>
>
> --
> Federica Magnoni
> Istituto Nazionale di Geofisica e Vulcanologia (INGV)
> Via di Vigna Murata, 605
> 00143 ROMA, Italy
> e-mail: federica.magnoni at ingv.it <mailto:federica.magnoni at ingv.it>
>
--
Dimitri Komatitsch, CNRS Research Director (DR CNRS)
Laboratory of Mechanics and Acoustics, Marseille, France
http://komatitsch.free.fr
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