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

[Federica Magnoni]

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>
:

> 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 <+91%2040%202301%208457>
>> > 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
>> >     _______________________________________________
>> >     CIG-SEISMO mailing list
>> >     CIG-SEISMO at geodynamics.org <mailto:CIG-SEISMO at geodynamics.org>
>> >     http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-seismo
>> >     <http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-seismo>
>> >
>> >
>> >
>> >
>> > _______________________________________________
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>> > 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
>>
>


-- 
Federica Magnoni
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Via di Vigna Murata, 605
00143 ROMA, Italy
e-mail: federica.magnoni at ingv.it
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