DETERMINATION OF GROUND MODULI BY A SEISMIC NOISE TECHNIQUE ON LAND AND ON THE SEA BED

Seismic noise appears to be present at the surface of the earth in varying degrees. It is familiar as a background signal when seismic refraction surveys and similar geophysical measurements are being carried out. The source of this noise appears to be partly atmospheric, and partly vehicle movement and other phenomena. That correlation techniques can be used for measuring surface wave velocities has been demonstrated by Roesler. Filtered white noise' signals were applied to an electromagnetic vibrator and the correlation observed with a signal transmitted through the ground and detected by a geophone. In the technique using seismic noise, correlation is observed between signals recorded from three geophones in a triangular array. The recordings are of the naturally occurring seismic noise. The test method, interpretation of results and calculation of dynamic moduli are described. Measurements were made at three sites. The authors concluded that seismic noise may be used to determine the variation of shear wave velocity with depth, the advantage of the technique being that deep measurements may be made easily without large vibration generators. The measurements also showed that the siffness properties of the boulder clay, the London clay and the Barton clay of the Christchurch Bay sea bed were similar. (TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00168505
• Corporate Authors:

  Institution of Civil Engineers

  One Great George Street, Westminster
  London,   United Kingdom  SW1P 3AA
• Authors:
  • Abbiss, C P
  • Ashby, K D
• Publication Date: 1983-12

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: p. 445-450
• Serial:
  • GEOTECHNIQUE
  • Volume: 33
  • Issue Number: 4
  • Publisher: Thomas Telford Limited
  • ISSN: 0016-8505

Subject/Index Terms

• TRT Terms: Clay; Depth; Earthquakes; Elastic waves; Measurement; Modulus; Noise; Ocean bottom soils; Seismicity; Shear strength; Soils; Sound; Stiffness; Till; Underwater construction; Underwater structures; Velocity; Wave motion; Waves
• Uncontrolled Terms: Ground; Wave velocity
• Geographic Terms: United Kingdom
• Old TRIS Terms: Sea floor; Seismic noise
• ITRD Terms: 4198: Boulder clay; 4177: Clay; 6499: Depth; 6136: Measurement; 5731: Seismic; 5531: Shear; 4156: Soil; 6748: Sound; 5408: Speed; 5931: Stiffness; 3626: Underwater; 8119: United Kingdom; 6767: Wave
• Subject Areas: Bridges and other structures; Environment; Geotechnology; Highways;

Filing Info

• Accession Number: 00384567
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: May 30 1984 12:00AM