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Electronic Supplement for

The GEOSCOPE Program: Progress and Challenges during the Past 30 Years

Geneviève Roult, Jean-Paul Montagner, Barbara Romanowicz, Michel Cara, Daniel Rouland, Robert Pillet, Jean-François Karczewski, Luis Rivera, Eléonore Stutzmann, Alessia Maggi, and the GEOSCOPE team

Appendix 1—Station Information

Appendix 2—GEOSCOPE Roster 1982 to present

Appendix 3—complete acknowledgments

Figures S1–S8.

APPENDIX 1: STATION INFORMATION

EQUIPMENT

Seismometers



Eighty percent of GEOSCOPE stations are still equipped with STS-1 sensors (Figure S1). Because STS-1 is no longer manufactured by Streckeisen, replacing malfunctioning sensors is no longer possible, which leads us to fix them ourselves whenever possible or to install STS-2 sensors instead. STS-2 sensors are known to present higher noise at long periods and require particular conditions during their installation (Hanka 2000). Some island stations or stations close to the coast such as AIS, HDC, FDF, FOMA, MPG, and MBO are equipped with STS-2 seismometers, as are stations operated by GSN (TRIS), CEA/DASE (DZM, TAOE), or CTBTO (ATD). A few stations are equipped with both a vertical STS-1 and a three-component STS-2 (AIS, TRIS) as seen in Table 1 (main text). Our station instruments have a constant response in velocity between 360 s and 10 Hz in the case of an STS-1, and between 120 s and 10 Hz in the case of an STS-2. The details of the recorded channels are listed below.




channel

SEED name

unit

flat response

sampling rate

number of bits

Very Long Period

VH

m/s

360s*–20s

0.1 sps

24 or 26

Long Period

LH

m/s

360s*–2s

1 sps

24 or 26

Very Broadband

BH

m/s

360s*–10Hz

20 sps

21 or 24

Mass Position

LM

m/s2

0s–10Hz

1 sps

16

Temperature

LKI

°C




1 sps

16

Pressure

LDI

Pa




1 sps

16

*In stations equipped with STS-2 sensors the period is 120 s instead of 360 s.
Analog-to-Digital Converters (ADC)

The upgraded stations are all equipped with Quanterra type ADC converters, Q4120 series (Q4126-6 channels or Q4128-8 channels) or Q330 series (Q330-6 or Q330-HR).


Auxiliary Sensors

The stations have been progressively set up with pressure sensors (Streckeisen, Vaisala, or Effa-Druck microbarometers) and handmade thermometers. At the end of 2009, 16 stations were equipped with microbarometers and nine stations with microthermometers (Figure 8B, main text). A systematic installation of environmental sensors enables us to quantify the influence of the environment on seismic noise and to reduce the noise level of seismic data, especially at very long periods.


INSTALLATION

Many manuals exist regarding the installation of broadband seismometers (Holcomb and Hutt 1992; UCB 1997; Urhammer et al. 1998; Bormann 2002; Widmer-Schnidrig and Kurrle 2006). STS-1 seismometers of the GEOSCOPE network are protected against unfavorable environmental conditions such as wind, high diurnal or seasonal variations of temperature and atmospheric pressure, variations of the magnetic field, corrosion due to humidity, and possible flooding. First, they are enclosed inside metal boxes. Second, they are protected by hermetic glass bells, under partial vacuum, to avoid noise due to atmospheric pressure variations. In some stations, the glass bell is filled with fine Styrofoam seeds. The insulating boxes include internal fresh desiccant and external heat-reflecting blankets. Electric signals are fed through a hermetic plug. Very often, the ceramic plates supporting the seismometers are carefully cemented to the floor. In other cases, these plates are put down on a sand bed, held back by a rigid frame. Barometric variations may cause tilt noise on the ground but not on the ceramic plate. The vertical sensors are always under a vacuum; the quality of the vacuum is checked by adjusting the POS signal. The horizontal components are not always under a vacuum; some stations exhibit a lower noise level without a vacuum inside the glass bells.

Different techniques have been applied to orient the horizontal sensors, such as geodetic gyroscope or magnetic compass measurements or solar sighting. At some stations, it was necessary to use a geodetic gyroscope, for example in long tunnels or deep vaults. Precise orientation of the sensors, when available, was carefully marked on the floor or the pillar.
APPENDIX 2 - THE GEOSCOPE TEAM from 1982 to PRESENT

The GEOSCOPE team has continuously evolved during the past 25 years. When dedicated scientists, engineers, and technicians have retired, new generations have taken over, fostering the development of new tools to respond to the scientific challenges of their time. Currently, the staff working at IPGP and EOST leads the GEOSCOPE team. They are supported by the groups working at CEA/DASE, IPEV, and IRD.



IPGP

Scientific Directors

Data Center

Instrumentation

frame1

frame2

frame3




EOST

Scientific Directors

Data Center

Instrumentation

frame4

frame5

frame6



APPENDIX 3 - ACKNOWLEDGMENTS
Acknowledgments to people working in the GEOSCOPE team in the period 1981–2009:

Gérard Ball, Sylvie Barbier, Eric Basier, Pascal Bernard, Françoise Besset, Michèle Bitterly, Sébastien Bonaimé, Jean Borsenberger, Jean-Marc Brendlé, Jean-Michel Cantin, Michèle Caillard, Jean-Michel Cantin, Hugues Castarède, Chantal Condis, Pascal Dayre, Aymeric de Carfort, Anne-Sylvie de Bièvre, Anne Deschamps, Christiane Desfoux, Bernard Dole, Vincent Douet, Jean-François Fels, Danielle Fouassier, Florence Giangrande, Nicole Gillet, Gwénola Guiveneux, Saphira Hounsihoue, Jean-François Karczewski, Jean-Claude Koenig, Jean-Claude Lépine, Nicolas Leroy, Jean-Jacques Lévêque, Denise Lévy, Robert Longeon, Anne-Marie Margotteau, Jeannine Moncouilloux, Michel Morand, Alfred Müller, François Paillous, Constanza Pardo, Geneviève Patau, Sandrine Pelletier, Frédérick Pesqueira, Nicole Pomarel, Annick Pyrolley, Marie-Christine Roche, Olivier Rozier, Jean Savary, Jean-Marie Saurel, Eugène Speisser, Daniel Streng, Jean-Yves Thoré, Jeannot Trampert, and Anne Wermelinger.


Acknowledgments to all people contributing:

It is difficult to name everybody, but we would like to thank all the researchers, engineers, and technicians who have worked and are still working with us in France or in their respective countries, including:


Anis Abdallah, Vitaly Adushkin, Tim Ahern, Nourredine Akacem, Nelson Allende, Donald Anderson, Kent Anderson, Olivier Andrieu, Sok Appadu, Carlos Aranda, Marcelo Assumpcao, Luciana Astiz, Catherine Baldassari, Sergio Barrientos, Sarah Bazin, Hadj Benhallou, Abdelhamid Bendekken, Jonathan Berger, Rosa Bernal, Jesus Berrocal, Mourad Bezzegoud, Mike Blackford, Rémy Bossu, Jacques Bouchez, Jacques Boulesgue, Boris Bukchin, Ray Buland, Rhett Butler, Jean-Philippe Caminade, Jaime Campos, Yves Cansi, Yves Caristan, Claude Cavoit, David Novello Casanova, Philippe Catherine, Eric Clévédé, Jean-Claude Delmond, Roger Decourt, John Derr, Jean-Michel Devaux, V.P. Dimri, Chuck Doll, Bernard Dost, Vincent Douet, Balraj Dunputh, Alexei Egorkin, Bruno Feignier, Célia Fernandez, Roger Foy, Yoshio Fukao, Germinal Gabalda, Luis Gailhardo, Christian Garita, Michel Gissang, Alejandro Gonzalez, Dimitri Gounbin, Larissa Gounbina, Fembe Goutbeek, Philippe Guerendel, Cyril Guinet, Winfried Hanka, Alain Hauser, Andres Heinloo, Mohamed Hfaiedh, Gary Holcomb, Jean-Marie Holl, Robert Hutt, Mohammed Jalludin, Gilbert Juste, Sophie Jymmikone, Brian Kennett, Valentin Kovalev, Vladimir Kulikov, Ogie Kuraica, V.N. Kovaliov, Philippe Kowalski, Carène Larmat, Jean-Louis Laurent, Frédéric Lauret, Thorne Lay, David Lazo, Pierre Lebellegard, Anatoli Levshin, Philippe Lognonné, Marc Lointier, Rémy Louat, Raul Madariaga, Karen Mac Nally, Bernard Massinon, Luis Mendes Victor, Yves Ménéchal, Lucien Mollard, Eli Morris, M. Morfin, Philippe Morisset, Nicolas Moutou, Abdou Salam Ndiath, David Nakedau, Alex Nercessian, Ann Ngo, Caryl Peterson, Jean-Louis Plantet, Kusalya Surya Prakacham, Marino Protti, Herb Mac Queen, Luis Quintanar, Vijaya Raghavan, Andry Ramanantsoa, Gérard Rambolamanana, Ramakrishna Rao, Marc Régnier, Dominique Reymond, Jean Roques, Yang Zhi Rong, Olivier Roult, Gérard Ruzié, Daniel Sampson, Jean-Marie Saurel, William Schillinger, François Schindele, Nikolaï Shapiro, David Simpson, Krishna Singh, Annie Souriau, Spiro Spiliopoulos, Oleg Starovoit, Joseph Steim, Sandy Stromme, Gerardo Suarez, Chad Trabant, Torild Van Eck, Isao Yamada, Abdelkrim Yelles-Chaouch, Jean-Pierre Viodé, Ruoping Wei, Boming Zhang, and the annual scientific and technical teams maintaining the stations of the South Indian Ocean and Antarctica in TAAF territories.
References to appendixes 1, 2, and 3

Bormann, P., ed. (2002). IASPEI New Manual of Seismological Observatory Practice. Potsdam, Germany: GeoForschungsZentrum Potsdam, ISBN 3-9808780-0-7.


Holcomb, L. G., and C. R. Hutt (1992). An Evaluation of Installation Methods for STS-1 Seismometers. USGS Open File Report 92-302.
Hanka, W. (2000). Which parameters influence the very long period performance of a seismological station? Examples from the GEOFON network; http://www.gfz-potsdam.de/geofon/manual.
UCB Seismological Laboratory at Berkeley (1997). Guidelines for installing broadband seismic instrumentation; http://www.seismo.berkeley.edu/seismo/bdsn/instrumentation/guidelines.html .
Urhammer, R. A., W. Karavas, and B. Romanowicz (1998). Broadband seismic station installation guidelines. Seismological Research Letters 69, 15–26.
Widmer-Schnidrig, R., and D. Kurrle (2006). Evaluation of installation methods for Streckeisen STS-2 seismometers, http://www.geophys.uni-stuttgart.de/~widmer.
Wielandt, E., and G. Streckeisen (1982). The leaf-spring seismometer: Design and performance. Bulletin of the Seismological Society of America 72, 2,349–2,368.

Figures

Figure S1. FDSN and GEOSCOPE networks in 2000, with indication of sensors at GEOSCOPE stations (80% of stations equipped with STS-1 sensors and 20% of stations equipped with STS-2 sensors).
Figure S2.

A) Photographs of the STS-1, first-generation vertical sensor (Wielandt and Streckeisen 1982).

B) Photograph of an STS-2 sensor

C) Digitizers: the present upgrade corresponds to the installation of standardized digitizers such as the Q330-HR ADC ones.


Figure S3: GEOSCOPE data from 1982 to 2009

A) The 36 distributed CD-Roms. Due to the increasing number of stations and channels, the data time length stored on each CD-Rom was decreasing with time.

B) After a restricted distribution (by request only) until the year 1992, 36 CD-Rom were distributed, from 1990 to 1998.

C) Archived data volume. The growth illustrates the simultaneous increasing number of stations and of recorded channels, with the change from a triggered way of proceeding to a continuous one.

D) Distributed data volume since 2000. Various distribution methods were used: event or continuous data distribution (through the anonymous ftp and the Web site) and the NetDC procedure since 2002.
Figure S4

A) More and more joint stations: presently seven stations are operating in the framework of cooperation agreements: KIP and TRIS with GSN/IRIS/USGS; DZM and TAOE with the French military agency CEA/DASE; ATD with CTBTO; CAN with ANU and GA institutions; INU with ERI.

B) Northern Hemisphere: a cooperation agreement between IPGP and GSRAS in Russia will help with the installation of a new site at VOR (Vorkuta) and upgrading SEY station by moving it to KAM (Kamchatka) .

C) Southern Hemisphere: EOST actively participated with Dôme C (CONCORDIA) station in cooperation with INGV (Italy), and in the 2007–2008 POLENET IPY (International Polar Year).


Figure S5. Distribution of the GEOSCOPE stations in 2000 with indication of the state of the art at that time. Remotely accessible stations corresponded to a phone line transmission, for large events only (Ms > 6.5).
Figure S6. Real-time link between the RER station (La Réunion Island) to the GEOSCOPE Data Center in Paris. More than 3 km of optic fiber has been deployed to conduct the signal outside the tunnel. Then, an ethernet bridge loads the signal to the roof of the St. Benoit College, where ADSL is operating.
Figure S7. All large earthquakes of year 2009 for which source mechanism parameters have been determined by Clévédé and Patau (2009, personal communication). See also http://geoscope.ipgp.fr.
Figure S8. The CNATOI (Centre National d’Alerte aux Tsunamis dans l’Océan Indien/National Center of Tsunami Warning in the Indian Ocean) initiated the upgrade of the six existing GEOSCOPE stations located in the Indian Ocean (AIS, ATD, CAN, CRZF, DRV, PAF, RER) where possible satellite data transmission was available, as well as the installation of two new sites (MAD/FOMA and ROD. At present: data is stored at the GEOSCOPE Data Center in Paris and can be fetched by all operational tsunami warning centers around the world, such as PTWC, JMA, GITEWS, ATWS, etc. In the future, data are planned to be sent to a unique local warning center.




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