Accession Number:

ADA191960

Title:

Low Frequency Seismo-Acoustic Propagation in a Sloping Ocean Environment: Measured Results and Numerical Predictions

Descriptive Note:

Final rept.

Corporate Author:

NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY STENNIS SPACE CENTER MS

Report Date:

1987-11-01

Pagination or Media Count:

21.0

Abstract:

As part of continuing program to investigate the characteristics of acoustic propagation and ambient noise in the very low frequency regime 20 Hz and less. Ninety -seven experiments were conducted off the Southeastern coast of the U.S. Cape Fear in 1985. Preliminary results of the Cape Fear data analysis have already shed some light on seismo-acoustic propagation. At the source-receiver ranges thus far considered, considerable penetration into the bottom is evident, particularly at frequencies below about 20 Hz. Both body and Scholte waves appear to contribute to the propagation in the sediment. Under certain conditions, the net SN ratio of the vertical geophone sensor is at least 6 dB higher than that of the hydrophone. Although examination of the depth dependence of the waterborne transmission loss as a function of range is still in process, spot checks at several ranges do indicate agreement between the model IFDPE and measured results hydrophone array. The SAFARI and IFDPE models provide some insight into certain aspects of the propagation, but alone, neither is sufficient for the environment considered. It is expected that models based on the finite difference method will be more appropriate. Keywords Ocean water column Sea bottom Sound propagation Seismic wave Waterborne sound source.

Subject Categories:

  • Physical and Dynamic Oceanography
  • Seismology
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE