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Title: Seismic Monitoring at the Underground Nuclear Research Laboratory in Mol, Belgium - 12461

Abstract

Micro-seismic piezoelectric transmitters installed in the Boom Clay at HADES produce predominantly high frequency signals, above 5 kHz, which favour the generation of P waves. However, above 5 kHz shear (S) waves are not detected by the installation. Recent studies at HADES indicate that it is possible to detect S waves with the current setup when applying a low (5 kHz) cut-off filter. The results also show that S waves have frequencies mainly below 1 kHz, while P waves are detectable at all of the eight transmitted frequencies but show optimum resolution in the range of 7 to 23 kHz. Although the system offers great potential for monitoring the evolution of a geological disposal site, further improvements in signal generation and treatment are necessary. One of these includes the design and testing of a new S-wave source at HADES planned in the framework of the EC MoDeRn project (http://www.modern-fp7.eu/). The seismic installation at HADES continues to provide useful information on the changing properties of the Boom Clay in the near and far field around the PRACLAY gallery since its start of operation in 2006. In the future, the system will also monitor the PRACLAY heater experiment that will start inmore » 2012 and go on for 10 years. So far, the results of long term seismic monitoring show that S waves contain frequencies mainly below 1 kHz. The P waves are detectable at all of the eight transmitted frequencies but show optimum resolution in the range of 7 to 23 kHz. To improve the signal-to-noise ratio and detection of S waves at HADES it is, therefore, necessary to apply a strong low-pass filter that matches the S-wave frequency content. Due to the different frequency ranges observed for the P and S waves, it is recommended to treat them separately. The evolution of both P and S wave velocities in the EDZ around the PRACLAY gallery show continued recovery since its construction in 2007. Modelling results of the variation in crack density obtained from the inversion of the modelled P-wave transmission velocities further confirm the recovery of the EDZ and the self-healing properties of the Boom Clay. (authors)« less

Authors:
 [1];  [2]; ;  [3]
  1. SCK.CEN/EIG Euridice and VUB, Mol (Belgium)
  2. SCK.CEN/EIG Euridice, Mol (Belgium)
  3. GMuG Gesellschaft fuer Materialpruefung und Geophysik mbH, Bad Nauheim (Germany)
Publication Date:
Research Org.:
WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States)
OSTI Identifier:
22293689
Report Number(s):
INIS-US-14-WM-12461
TRN: US14V1345115213
Resource Type:
Conference
Resource Relation:
Conference: WM2012: Waste Management 2012 conference on improving the future in waste management, Phoenix, AZ (United States), 26 Feb - 1 Mar 2012; Other Information: Country of input: France; 2 refs.
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 58 GEOSCIENCES; BOOM CLAY; DETECTION; KHZ RANGE; MONITORING; P WAVES; S WAVES; SIMULATION; TESTING; TRANSMISSION

Citation Formats

Areias, Lou, Verstricht, Jan, Fischer, Thomas, and Philipp, Joachim. Seismic Monitoring at the Underground Nuclear Research Laboratory in Mol, Belgium - 12461. United States: N. p., 2012. Web.
Areias, Lou, Verstricht, Jan, Fischer, Thomas, & Philipp, Joachim. Seismic Monitoring at the Underground Nuclear Research Laboratory in Mol, Belgium - 12461. United States.
Areias, Lou, Verstricht, Jan, Fischer, Thomas, and Philipp, Joachim. Sun . "Seismic Monitoring at the Underground Nuclear Research Laboratory in Mol, Belgium - 12461". United States.
@article{osti_22293689,
title = {Seismic Monitoring at the Underground Nuclear Research Laboratory in Mol, Belgium - 12461},
author = {Areias, Lou and Verstricht, Jan and Fischer, Thomas and Philipp, Joachim},
abstractNote = {Micro-seismic piezoelectric transmitters installed in the Boom Clay at HADES produce predominantly high frequency signals, above 5 kHz, which favour the generation of P waves. However, above 5 kHz shear (S) waves are not detected by the installation. Recent studies at HADES indicate that it is possible to detect S waves with the current setup when applying a low (5 kHz) cut-off filter. The results also show that S waves have frequencies mainly below 1 kHz, while P waves are detectable at all of the eight transmitted frequencies but show optimum resolution in the range of 7 to 23 kHz. Although the system offers great potential for monitoring the evolution of a geological disposal site, further improvements in signal generation and treatment are necessary. One of these includes the design and testing of a new S-wave source at HADES planned in the framework of the EC MoDeRn project (http://www.modern-fp7.eu/). The seismic installation at HADES continues to provide useful information on the changing properties of the Boom Clay in the near and far field around the PRACLAY gallery since its start of operation in 2006. In the future, the system will also monitor the PRACLAY heater experiment that will start in 2012 and go on for 10 years. So far, the results of long term seismic monitoring show that S waves contain frequencies mainly below 1 kHz. The P waves are detectable at all of the eight transmitted frequencies but show optimum resolution in the range of 7 to 23 kHz. To improve the signal-to-noise ratio and detection of S waves at HADES it is, therefore, necessary to apply a strong low-pass filter that matches the S-wave frequency content. Due to the different frequency ranges observed for the P and S waves, it is recommended to treat them separately. The evolution of both P and S wave velocities in the EDZ around the PRACLAY gallery show continued recovery since its construction in 2007. Modelling results of the variation in crack density obtained from the inversion of the modelled P-wave transmission velocities further confirm the recovery of the EDZ and the self-healing properties of the Boom Clay. (authors)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {7}
}

Conference:
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