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NERIES |
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Transnational Access Activity (TA2)
CEA/DASE: Access grants for verification seismology
The infrastructure of the TA2 is located in Bruyères-le-Châtel (Essonne, France), approximately 35 km south of Paris on the premises of the Direction des Applications Militaires of the CEA. DASE has a long history of bilateral collaboration with institutions worldwide. The scientific collaborations have developed through extended visits of seismologists, training of PhD students and joint work such as the seismic hazard assessment of towns or regions, the establishment of seismicity maps and source and propagation studies. These collaborations have extensively benefited from this facility.
The user will work in the building where the French National Data Centre is located. A room which can accommodate up to 4 researchers will be made available.
Users will be provided both Unix and/or PC computers granting them access to the necessary databases. The computers will also contain all relevant data processing software and event characterization software. More specific items can also be included if necessary such as tools to assess the detectability of seismic or infrasound networks, array response, seismic and infrasound wave propagation modelling.
From the same building, access will also be possible to workstations allowing for computations requiring large CPU time or the massively parallel computer hosted by the CEA.
Each user will be followed by one person from the French National Data Centre to assist him/her with logistical, technical and scientific matters.
The TA2 (verification seismology) provides access to :
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 1. Seismic Data Base of earthquakes and quarry blasts in France |
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2. Infrasound Data Base |
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3. Real time process: automatic detection/characterization/location |
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4. Source inversion / Direct simulation |
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5. Automatic fusion of seismic bulletins |
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6. Specific process: array analysis (PMCC), depth estimation (pP/sP), AI classification |
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7. Possibility to access to the massively parallel computer |
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How to submit a proposal for access grants? : |
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The proposal must be submitted to the CEA/DASE and/or to the NERIES management. This proposal is made of a scientific program and Curriculum Vitae. The proposal should include the scientific goals of the research with a brief description of the previous works and the needs in term of infrastructure. This description does not be longer than 3-4 pages max.
Clearance is required to enter the site, which requires that the user provides specific information. The delay to obtain the required clearance is 3 weeks for a one week stay and 6 weeks for a one to two months stay for EU citizens.
A international selection committee will meet several time per year to review proposal.
The scientific contact for the TA2 is: |
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| Dr Jocelyn GUILBERT |
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| Bâtiment SABLES |
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| BP12 |
Fax: (33) 169-267-000 |
| 91680 Bruyères-le-Châtel, FRANCE |
Email: jocelyn.guilbert[at]cea.fr |
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For further information, see: www.orfeus-eu.org/neries/neries.htm |
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CEA/DASE: a brief description |
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 History / Location
The Département Analyse, Surveillance, Environnement of the Direction des Applications Militaires of the French Commissariat à l’Energie Atomique (CEA -Atomic Energy Commission) has been in charge of the detection of nuclear explosions worldwide since the 1950’s. Founded by Professor Y. Rocard, the Laboratoire de Détection et de Géophysique (LDG), now part of the DASE, has a vast experience of designing geophysical sensors, deploying and operating geophysical networks, processing geophysical data ultimately leading to discriminating natural and artificial geophysical events.
During the 1950’s, the first seismic and infrasound sensors were designed. Such sensors have continuously evolved and are at the leading edge today. They are being widely used for the Comprehensive Nuclear Test Ban Treaty (CTBT). For example, DASE infrasound MB2000 sensor is selected for approximately 80% of all infrasound stations of the CTBT verification system.
History / Location
In the 1960’s, the DASE deployed its first permanent seismic network in France (see figure below). This network is
still in operation today, allowing the build-up of a unique database for geophysical studies. Since 1995, the network
records high dynamic digital data transmitted in real time through V-sat. In the 1990s, an infrasound array was also
deployed in Normandy and has been operating since. Alongside with the deployment of geophysical networks, methods for
operational data processing have been developed at DASE. These tools are directly connected to the database and offer
an extremely efficient set-up for the handling of large data sets. Each year over 6000 seismic events are being
located at DASE, representing the analysis of over 200,000 seismograms per year. This system is the one being used
for the French seismic alert system and is, therefore, operational 24h/day. For array processing, the PMCC software
was developed in the 1990’s. This code is now used by several geophysical observatories worldwide and installed at
the International Data Centre of the CTBT as the operational processing tool for infrasound data.
In the context of the CTBT, DASE is in charge of installing and operating all 16 stations (from the 4 technologies
seismic, infrasound, hydroacoustic and radionuclide) on French territory. Furthermore, 8 more stations are being
installed by DASE in collaboration with other countries (Bolivia, Mongolia, Madagascar, Ivory Coast). The DASE is
one of the leading organisations contributing to the setting up of the International Monitoring System and
International Data Centre of the CTBT. The combination of expertise in these different fields is quite unique
in Europe and leads to major research achievements. This has been particularly evident recently in the field of
seismo-acoustic coupling where the imaging of the seismic rupture using infrasound data generated three papers
in major international journals and several oral presentations in meetings.
This gathering of expertise, from sensor and network design to advanced data processing, is complementary to the
one developed by NORSAR where expertise is focused on array processing.
Finally, the CEA has decided a few years ago, to locate its main computer centre in Bruyères-le-Châtel (35 km south
of Paris), which is where the DASE is located. This massively parallel computer, which is one of the largest in
Europe, is now being used by DASE for advanced geophysical modelling. In particular, new concepts of
three-dimensional high-frequency wave simulation can be tested.
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Scientific proposal |
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The TA2 (verification
seismology) allows scientific users to obtain a privileged access to one of the most homogeneous seismological
database in Europe. DASE has a long history of bilateral collaboration with institutions worldwide. The scientific
collaborations have developed through extended visits of seismologists, training of PhD students and joint work such
as the seismic hazard assessment of towns or regions, the establishment of seismicity maps. These collaborations have
extensively benefited from this facility.
1. Seismic Data Base of earthquakes
and quarry blasts in France
The Database will contain the seismological bulletin of regional events over the time period of 1962-2005. The bulletin
is reviewed by analysts who manually label each event to distinguish natural earthquake or quarry blast. The bulletin
contains the location using the LDG seismic model, the local magnitude (ML) and the manual phase picking and label. The
seismic waveforms are also available at all stations of the LDG seismic network (see the following figure) since it has
become digital.
All these information (bulletin and waveform) will be made available for consultation thanks to home-made libraries
(Matlab/Fortran/C) or via the Onyx interactive software (see the figure below):
 Example of Onyx interactive program (phase picking, automatic amplitude measurement, location)
This high-quality database covering 40 years of seismic monitoring provides an ideal set up for testing software. It is the reference for seismic hazard assessment studies in France.
2. Infrasound
For infrasound studies, data collected through DASE experimental station located in Flers (Normandy), will be made available. Since the data cover several years of recording of natural and man-made sources, a large variety of scientific studies can be undertaken. These data have already been used extensively to model the high-altitude winds and to validate infrasound propagation modelling codes or to study the seismo-acoustic signature of quarry blasts.
The infrasound data available for the present transnational access activity are listed below:
- A selection of infrasound waveforms associated with ‘natural’ phenomena such as lightning effect (storm), earthquakes, quarry blasts, volcanoes or sonic bangs of Concorde aircraft.
- PMCC bulletin of detections over a selected time window
The following figure gives an example of the PMCC detection for the infrasonic signals generated by daily supersonic Concorde between North America and Europe:
Example of PMCC detection for a Concorde infrasonic signal recording at Flers station.
3. Real time process: automatic detection/characterization/location
Since 1990’s, DASE has developed a suite of software to detect, characterize and localize seismic events. The following list described each software available for users:
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1) OPL_SIMU: this software permits to simulate a ‘real-time’ continuous flow of data to test the real-time detection program. It is very useful if you want to benchmark a detection program in ‘quasi’ real condition. |
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2) DT_PMCC: This program is a real-time detector based on the PMCC algorithm. It is well-adapted for seismic and infrasound array processing to detect and characterize the coherent wave front crossing an array. |
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3) BERYL: this software is the program used for the automatic event location at regional and teleseismic distance with the French seismic network. This program integrates two automatic phase picking algorithms especially well-adapted to signal at regional and teleseismic distances. The outputs are stored in the data base and can then easily be analysed using the Onyx software. |
4. Source inversion / Direct simulation
The newly developed platform for detailed event processing offers the unique opportunity to interface scientific software with our database structure. This platform also offers the capability to easily retrieve data from all major data centres (IRIS, USGS …). In the framework of the NERIES proposal, access to the ORFEUS data centre will also be implemented. This interactive interface permits to link all events in the data base, IRIS and/or ORFEUS waveforms with:
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1) sophisticated program of kinematic inversion based on slip patches representation |
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2) direct simulation using AXITRA or equivalent programs (3D fault representation, point source, moment tensor, force …) |
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3) pP estimation based on the cepstrum/F-statistics analysis |
This program is an interesting platform to easily benchmark different codes of source inversion or direct simulation.
(a) Interactive interface of the software is giving access to the data base, IRIS and ORFEUS waveforms. On the same interface you can compute a complex inversion of the seismic source or compute a direct simulation to test a rupture model. (b) Example of kinematic inversion for the Boumerdès event and split patch distribution along the fault.
5. Automatic fusion of seismic bulletin
A few years ago, 10 european countries, coordinated by DASE, joined their efforts in evaluating the quality of the
seismological bulletin provided by the Prototype International Data Centre. Three software written in Italy, Sweden
and France (DASE) were tested and compared. This lead to the definition of new software for bulletin fusion and
bulletin comparison. The Fusion algorithm was developed by DASE to mix seismic bulletins provided by different
institutes and allows to obtain a homogeneous bulletin by mixing all the data available (arrival time, azimuth,
slowness). This program is currently intensively used by the EMSC to compute the automatic location for the WEB
page and the Euro-Mediterranean bulletin (1998-2003).
Example of result obtained using the Fusion software for the Euro-Mediterranean bulletin
6. Specific process: array analysis (PMCC), depth estimation (pP/sP), AI classification
Different software tools are also available for specific studies. These programs represent a very useful set up for testing software in term of automatic/interactive (1) depth estimation, (2) array processing (seismology or infrasound) or (1) event classification.
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1) Depth estimation: based on ceptrum/F-statistic approach, this program offers an interesting
approach of the depth estimation. The homomorphic transformation and F-statistic signal processing permits to
pick an echo (secondary arrival) after the P-wave arrival using a statistical Signal/Noise ratio filter on the
cepstrum signal over an array. This approach is very useful for an automatic phase picking of secondary arrivals
(pP, sP or PcP). |
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2) Array processing: For array processing, the PMCC software (Progressive Multi-Channel
Correlation method) was developed in the 1990’s. This code is now used by several geophysical observatories
worldwide and installed at the International Data Centre of the CTBT as the operational processing tool for
infrasound data. PMCC, a method allowing for efficient low signal-to-noise detection and parameter extraction,
was originally written for seismic array detection but has since proven its capacity for infrasound and
hydroacoustic data as well. Over 10 institutions, three of them being European, have access to the software and
are using it on a regular basis. A PMCC user group has been created and its first meeting was hold in 2005.
Beside PMCC, several collaborations with other organizations are developing where DASE is making its knowledge
and software available to seismologists.
Example of the WinPMCC interface (in this case, the array analysis of the seismic signal crossing the Alps during the Giant Sumatra earthquake) |
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3) Artificial Intelligence Classification:
Event classification to identify the name of a seismic event (eq, qb, rb …etc.) has always been a difficult and
time consuming task.
We use classifiers based on Multi-Layer Perceptrons and Support Vector Machines to classify seismic events that
occurred in metropolitan France. This processing requires large datasets to allow the learning of the neural
network. The results are used in the software RAMSES to help the seismic analysts to conduct efficiently the
revision of the weekly French seismic bulletin. With 96.5% of good classification, and less than 7% of the events
that require expert verification, RAMSES strikingly improves the speed of the bulletin revision. This software
uses intensively the data base and allows to quickly check the result of computation by way of a user-friendly
interface.
RAMSES screenshot. In the present case, there is a conflict between the analyst's label and the automatic classifier (see box) for the selected event (see arrow)
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Description of the infrastructure |
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The infrastructure is composed as follows:
The Database gives access to the bulletin in term of origins (location), arrivals (phase picking) and waveforms. The data are available trough Onyx, SQL and are easily usable with Fortran, C, Matlab software. The computers and the Operating System are selected as the most common academic infrastructure.
The computers will also contain all relevant data processing software and event characterization software. More specific items can also be included if necessary such as tools to assess the detectability of seismic or infrasound networks, array response, seismic and infrasound wave propagation modelling. The configuration could be updated to correspond to specific scientific proposals but it is strongly recommended to use the most common compilers, Operating System and freeware programs.
If necessary, access will also be possible to workstations allowing for computations requiring large CPU time or the massively parallel computer.
Each user will be followed by one person from the French National Data Centre to assist him/her with logistical, technical and scientific matters.
It is expected that users might come to work either in close relation with the DASE researchers for joint research studies or more independently to test and evaluate their own software or process their own data with DASE software. In the first case, scientific support will be provided by DASE as needed. The scientific environment at DASE consists of about 50 engineers and researchers in the various fields of internal and external geophysics. Some of these researchers are known internationally in their field of expertise. Numerous collaborations already exist with French universities, in particular through joint Ph.D. theses.
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Accessibility to the infrastructure |
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The infrastructure of the TA2 is located in Bruyères-le-Châtel (Essonne, France), approximately 35 km south of Paris on the premises of the Direction des Applications Militaires of the CEA.
Since Bruyères-le-Châtel is located far from Paris, over 50 buses run every day from the whole Paris area towards the research center to bring CEA personnel. These buses are free, they arrive at the center at 8:30 a.m and leave at 5 p.m. Therefore, it is extremely easy to stay in Paris and come to work daily in Bruyères-le-Châtel.
The user will work in the building where the French National Data Centre is located. A room which can accommodate up to 4 researchers will be made available.
Clearance is required to enter the site, which requires that the user provides specific information. The delay to obtain the required clearance is 3 weeks for a one week stay and 6 weeks for a one to two months stay for EU citizens.
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Reporting requirements
Before the end of the visit, all visitors have to report about the work done at the infrastructure, answering an EC questionnaire
about their visit, and all future publications using results of their visits must acknowledge the received support by the NERIES
Project, EC Contract Number 026130. |
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Summary of Bibliography |
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Y. Cansi: An automatic seismic event processing for detection and location: The PMCC method. Geophys. Res. Lett., 22, 1021-1024, 1995
A. Le Pichon, M. Garcés, E. Blanc and M. Barthélémy : Acoustic propagation and atmosphere characteristics derived from infrasonic waves generated by the Concorde. J. Acoust. Soc. Am., 111, 629-641, 2002
A. Le Pichon, J. Guilbert and M. Vallée: Infrasonic imaging of the Kunlun Mountains for the great 2001 China earthquake. Geophys. Res. Lett., vol.30, NO. 15, 2003
A. Le Pichon, J. Guilbert and M. Van de Walle: Ground-coupled air waves and diffracted infrasounds from the Arequipa earthquake of June 23, 2002. Geophys. Res. Lett., 2003
J. Perrot, P. Arroucau, J. Guilbert, J. Déverchère, Y. Mazabraud, J. Rolet, A. Mocquet, M. Mousseau and L. Matias : Analysis of the Mw 4.3 Lorient earthquake sequence: a multidisciplinary approach to the geodynamics of the Armorican Massif, westernmost France. G. J. Int., Vol. 162, Issue 3, Page 935-950, 2005
Y. Mazabraud, N. Béthoux, J. Guilbert and O. Bellier : Evidence for short-scale stress field variations within intraplate central-western France. G. J. Int.,Vol. 160, Issue 1, Page 161-178, 2005
J. Guilbert : Le CEPSTRE: Définition et exemples d’utilisation en hydroacoustique et en sismologie. Traitemement du signal pour géologues et géophysiciens, Techniques avancées n°3, 2004, ISBN 2-7108-0785-8, 191-199.
J. Guilbert, M. Vallée, A.Le Pichon, J. Vergoz and M. Ulziibat: Source inversion, Earth-Atmosphere ground coupling. Research and Technology Review, National Nuclear Center of the Republic of Kazakhstan. Issue 2(18), June 2004 :ISSN 1729-7516
D., Mercier, M., Aupetit: How to help seismic analysts to verify the French seismic bulletin?. Engineering Applications of Artificial Intelligence, Elsevier, (in press 2006)
S. Godey, R. Bossu, J. Guilbert and J.Mazet Roux: A comprehensive seismological bulletin at regional scale. SRL 77 (4) July/August 2006. 459-473 |
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