Accession Number:

ADA222933

Title:

Experiments and Analysis of Data on Shear Wave Propagation in Shallow Water Sediments

Descriptive Note:

Final rept. 11 Jan 1988-30 May 1990

Corporate Author:

RONDOUT ASSOCIATES INC STONE RIDGE NY

Report Date:

1990-06-01

Pagination or Media Count:

39.0

Abstract:

This research is to determine the physical parameters that control acoustic propagation in shallow water and their relationship to geological structure and processes to improve acoustic monitoring capability. Specific objectives were to develop instrumentation, field, procedures, and data inversion methods required for efficient high resolution determination of elastic parameters of bottom sediments as functions of depth and location, and to evaluate effects of lateral heterogeneity and anisotropy. Bottom mounted sources and receiving arrays were developed to effectively produce and record both longitudinal PSV, Rayleigh, StoneleyScholte wave and transverse SH, Love wave reflectionrefraction data. The shear generating sources used are designed to produce starboard pairs emphasize longitudinal energy differenced pairs emphasize transverse energy. A thirty element digital accelerometer hydrophone array also was developed and used. The elements of the array were also developed and used. The elements of the array have one meter spacing each consisting of three orthogonal accelerometers flat from 2 to 500 Hz, a hydrophone and a vertical direction sensor. Each of the 4 components recorded produces unique data that provide additional information on wave type, velocity attenuation structure, scattering, lateral heterogeneity, anisotropy, and instrument-bottom coupling possible signal distortion. This research has demonstrated that high resolution longitudinal and transverse mode shear data can be obtained in shallow water regions and inverted to obtain shear velocityattenuation vs. depth models.

Subject Categories:

  • Physical and Dynamic Oceanography
  • Acoustic Detection and Detectors
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE