GEOSCOPE in 2002

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GEOSCOPE in 2002

• Geneviève Roult
• FDSN meeting
• Hawaii, June 2002

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Meeting in Paris on March 25th, 2002 GEOSCOPE
its future

• Participants
• P. Vidal, J. Ludden, directors of INSU National
  Institute of Sciences of Universe (part of CNRS
  National Center of Scientific Research,
• A. Galdeano, representative of INSU,
• C. Jaupart, director of IPGP Institute of
  Physics of the Earth of Paris,
• P. Bernard, M. Cara, S. Chevrot, P. Dayre, A.
  Deschamps, M. Granet, A. Hirn, J.C Lépine, J.J.
  Lévêque, R. Louat, A. Mocquet, G. Poupinet, L.
  Riveira, G. Roult, A. Souriau, E. Stutzmann, J.P.
  Vilotte, J. Virieux, seismologists of the
  different french institutes (Paris, Strasbourg,
  Grenoble, Nice, Toulouse, Nantes),
• S. Barrientos, representative of CTBTO,
• F. Schindele, B. Feignier, representatives of
  CEA/DASE,
• T. Van Eck, representative of the european Data
  Center ORFEUS,
• T. Ahern, representative of the FDSN and the
  IRIS Consortium.
• Some points discussed at this meeting are
  presented on the following pages.

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G.Roult
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G.Roult
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DATA DISTRIBUTION

• 1 - CD-ROMs
•  
• 36 CD-ROMs spanning the period from March 1982 to
  July 1992, have been created. These CD-ROMs
  have been distributed worldwide.
• 2 - Anonymous ftp site (ftp//geoscope.ipgp.jussie
  u.fr)
• Events with Msgt6.3 or of particular interest are
  uploaded from 17 stations by phone line. The data
  are available within one or two days. 

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DATA DISTRIBUTION

• 3 - WWW server (http//geoscope.ipgp.jussieu.fr)
• Products  Station book Instrument responses
• Noise level plots Plots and data files of
  recent events
• Real-time data from SSB station (in France)
• Archived data files
•  
• 4 - NetDC (Networked Data Centers) procedure at
• netdc_at_ipgp.jussieu.fr 
• The best way to get information from all
  Networked Data Centers, Iris, UC Berkeley,
  Geoscope, Orfeus and Geofon.
• You can retrieve the INVentory
• the instrumental RESPonses
• the DATA directly to your disk

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Number of data requests in 2001 (NetDC procedure)
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Data volume through NetDC procedure (last quarter)
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Archive traffic / monthGeoscope data requests

• Remark data are distributed in SEED format. For
  the equivalence in SAC format multiply the volume
  by 4.

Geoscope DC Web site 110 2 000 1.6 Gbytes
Geoscope DC NetDC procedure 655 110 000 12
Gbytes
through thWebat Geoscopt requests seismogra
ms volume
IRIS_DMC NetDC procedure 150 6570 0.33
Gbytes
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The Geoscope stations are very important thanks
to their original geographical situation.
Example azimuthal distribution of the 1995 Jan
15th Kobe event
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Message to the FDSN Rayleigh wave train
clipping at some far stations,example Kobe
event, OBN station

• INU 202 km
• MDJ 1207 km
• SSE 1350 km
• ENH 2441 km
• OBN 7429 km

G.Patau/G.Roult
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What does GEOSCOPE provide?

• I - A unique station distribution that permits
• 1. Better azimuthal coverage ? seismic source
  studies
•  2. Ray paths not provided by other FDSN stations
  ? tomographic studies
•  3. Detection and location of events that would
  otherwise be overlooked in bulletins of global
  seismicity, thanks to our Southern Hemisphere
  stations
•  
•  

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(No Transcript)
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The near future

• Transfer the maintenance of some stations from
  IPGP to local authorities.
• Why? There are now many stations in the
  Northern Hemisphere, and sometimes at the same
  location.
• The black crosses on the next figure
  correspond to stations for which well reconsider
  that problem.

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G.Roult/S.Barbier
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The near future

• 1) Transfer the maintenance of some stations from
  IPGP to local authorities

• Install new sites that improve the global network
  (SEY and VOR in Russia)
• Why? SEY and VOR are located on the same
  meridians than frequent large events. The PKP
  waves provided by such polar paths will help our
  knowledge on anisotropy. See next figure.

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G.Roult
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The near future

• 1) Transfer the maintenance of some stations from
  IPGP to local authorities.
• 2) Install new sites that improve the global
  network (SEY and VOR in Russia).

• Standardize the acquisition chain (sensors,
  digitizers)
• Well keep our STS1 seismometers as long as
  possible
• We started to replace our old Streckeisen
  digitizers
• by Quanterra ones (Q4120 and Q330).

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The near future

• 1) Transfer the maintenance of some stations from
  IPGP to local authorities.
• 2) Install new sites (SEY and VOR in Russia).
• 3) Standardize the acquisition chain (sensors and
  digitizers).

• 4) Install microbarometers and thermometers in
  all stations.
• Why? To improve the signal to noise ratio by
  subtracting the atmospheric pressure effect. 7
  Geoscope stations are now equipped with
  microbarometers. See next figure.

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G.Roult/S.Barbier
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Why microbarometers?
Litterature Zürn Widmer (1995), Beauduin
(1996) New Guinea event of 1996 Feb 17th
(Ms8.1). Thin and thick lines correspond
respectively to spectra before and after
atmospheric pressure correction (Roult and
Crawford, 2000 )
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The near future

• 1) Transfer the maintenance of some stations from
  IPGP to local authorities...
• 2) Install new sites at high latitudes (VOR and
  SEY) ..
• 3) Standardize the acquisition chain..
• 4) Install microbarometers and thermometers...

• 5) Cooperate with the french military agency
  CEA/DASE to get real-time data at some stations
  (we disagree with the CTBTO solution).
• Five stations are involved by CTBTO. On the next
  figure the 3 red dots correspond to the near
  future.

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G.Roult
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Comparison ofCTBTO and DASE solutions

• CTBTO
• . Segmented data
• . High gain, frequent clipped records
• . Availability ???

• DASE
• . Continuous data at 20sps
• . Low gain in order to get no clipped records
  in case of large near events

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The near future

• 1) Transfer the maintenance of some stations
• 2) Install new sites at high latitudes..
• 3) Standardize the acquisition chain ..
• 4) Install microbarometers and thermometers...
•  
• 5) Cooperate with CEA/DASE/CTBTO to get real-time
  data..

• 6) Adopt the best adapted solution for every
  station to get real-time data.

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WHY REAL TIME ?

• Real time is necessary for quality control, in
  order to
• - know rapidly if the instruments are working
• - check time corrections
• - follow the instrument responses
• - react in case of problems
• - distribute rapidly correct data
• - help every Data Center to determine more
  precise CMTs
• - satisfy impatient scientists
• We are developping an automatic data process
  filling some regulations, acquisition, control,
  documentation, format data archiving

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The near future

• 1) Transfer the maintenance of some stations
  .....
• 2) Install new sites at high latitudes..
• 3) Standardize the acquisition chain..
• 4) Install microbarometers in all stations..
• 5) Cooperate with DASE/CTBT to get real-time
  data..
• 6) Adopt the best adapted real-time solution ...
  

• 7) Obtain a better path coverage of the Earth by
  cooperating with all ocean bottom projects.

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GEOSCOPE and the ocean bottom conquest

• At the present time, different concepts are
  being analysed
• in Japan, in Europ (France,)
• Well cooperate with any operational project in
  order to install a few stations on the ocean
  bottom floor, to provide a better instrumental
  coverage of the Earth.