Observatories and Research Facilities for EUropean Seismology
Volume 1, no 1 January 1999 Orfeus Newsletter


ORFEUS workshop

Geohysical Institute, Prague, Czech Republic. November 9 - 12, 1998

Torild van Eck
ORFEUS, Royal Netherlands Meteorological Institute, De Bilt, Netherlands
Introduction - Program and Items - Future workshops

Introduction

ORFEUS organized and sponsored in November 1998 a workshop in Prague at the Geophysical Institute of the Academy of Sciences of the Czech Republic (ASCR): "Installation and operation of broad-band seismograph stations". The workshop was an initiative from ORFEUS's Working Group 1 and Working Group 2. Jan Zednik, Axel Plesinger and Hana Kochova, all from the Geophysical Institute, stood for the local organisation.
41 participants and lecturers from 18 countries met during four days. Below follows a (very) short summary of the lectures in the program program. A number of these lectures will or are already available. Much of the practical information presented will be made available within Working Group 2.

Program and items

  • Winfried Hanka (Geofon), VBB systems and networks - introductory overview
    Broad-band seismometer developments: SRO-derivatives - KS26000 and KS54000 ; STS2 ; 6MG-3T. New developments: FBS-3 (SSB Beijing) ; JCZ-1 (SSB Wuhan) ; PMD Scientific Inc (USA).
    Dataloggers: gain ranging (12 bits) real 24 bit technology and 24 bit Delta-sigma technology. New developments: Earth Data PR2400 (real 24 bit technology)
    Federation of Digital Seismograph Networks (FDSN), GEOSCOPE, IRIS, GRSN, USNSN, GEOFON, etc.
    Seismometer installation. with Geofon's and GRSN's shielding techniques. Vaults. Datalogger and communication aspects.
    SeisComP (see software) concept

  • Damiano Pesaresi (MedNet), Installation & maintenance of VBB station
    Seismometer installation, noise and temperature isolation.
    Data Acquisition (DAQ) Systems - MedNet, like GEOFON operates Quanterra - GPS
    (Satelite) communication, mobile phone and wireless Internet: VSAT, INMARSAT
    Practical operational procedures and station examples.

  • Erhard Wielandt (Stuttgart), Force-balance seismometers - theory & calibration
    Principle of inertial seismometers (for example the STS-1 and STS-2).
    Poles and Zeros description of the system response
    Relative (electrical) calibration - software available at Stuttgart University
    Absolute (mechanical) calibration - presentation of effective (poor man's) method. Software available.

  • Reinoud Sleeman (ORFEUS), AutoDRM: concept and implementation
    presentation of AutoDRM for potential operators and users.

  • Axel Plesinger (GI ASCR, Prague), Transfer functions, system responses & calibration headers
    Theory of transfer functions, the Poles and Zeros description of the transfer function.
    Fourier, Laplace transform, Z-transforms. Amplitude and phase response, Minimum-phase systems.
    IIR (Infinite Impuls Response) and FIR (Finite Impuls Response) filters, causal and acausal filters.
    Calibration, MatLab based software available.

  • Frank Scherbaum (Potsdam), High resolution AD conversion & FIR filters
    FIR filters, principles of Sigma-Delta modulators, relevancy of accurate filtering (deconvolution) procedures, i.e. ground motion recovery.
    Stable deconvolution using minimum and maximum phase filters.
    Filtering and educational software available.

  • Roderick Stewart (CTBTO/IMS), CTBTO: International Monitoring System and Global Communication
    Presentation and explanation of the CTBT Organisation.
    Presentation activities of the IMS, discussions about the interaction between IMS (who bears the responsibility for verifying the systems) and the station/network operators.

  • Bernard Dost (ORFEUS) and Jan Zednik (GI ASCR, Prague), Data archiving and exchange, formats & format conversion
    Overview SEED (Standard for the Exchange of Earthquake Data), Data exchange facilities (AutoDRM, ftp, Internet).
    Format conversion (available software) overview.

  • Klaus Stammler (Gräfenberg), Basic data handling and analysis software
    Presentation of and hands-on training with Seismic Handler (SH), an (array) data analysis package used at Gräfenberg.

  • Neil Spriggs (Nanometrics), Satelite communication in seismology
    The potential of satelite communication: Ku-band technologies, presentation of Libra (Nanometrics), VSAT.

  • Dan Harvey (Boulder Real Time Technologies, Inc.), The Lodore Broadband Array
    Practical aspects of the (Kinemetrics) installation of a BB array with different remote data users. Presentation of the Antilope Seismic Information System (ASIS - a further development of DataScope).

  • Rhett Butler (IRIS), A Broadband Seismic Station on the Sea Floor: The Hawaii-2 Observatory
    Interesting 15 minutes summary video of the installation of a Deep Sea station connected to an old Pacific telephone cable for communication.

  • Genevieve Roult (GEOSCOPE), MOISE, an Experiment of Sea Floor Observatory
    Presentation on the French Ocean Bottom Observatories.

Future ORFEUS workshops

ORFEUS is planning a similar workshop with emphasis on "Installation, operation, data processing in experiments involving mobile (broad-band) seismic equipment" for autumn 1999. The planning of another workshop "Seismological software development with emphasis on Java" will be discussed at the IUGG99 in Birmingham. Any suggestions with regard to these plans are appreciated.

ORFEUS received much more applications for the 1998 ORFEUS workshop, however, only a limited number of people could be admitted. Please, let us know if you are interested in a repeat of the ORFEUS 1998 workshop. ( send an email to Torild van Eck).

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