Accession Number:

ADA516178

Title:

Infrasound Signals from Ground-Motion Sources

Descriptive Note:

Conference paper

Corporate Author:

LOS ALAMOS NATIONAL LAB ALBUQUERQUE NM

Personal Author(s):

• Whitaker, Rodney W.

Report Date:

2008-09-01

Pagination or Media Count:

10.0

Abstract:

This report presents progress on an ongoing research project looking at near-field infrasound signals as a basis for discriminants between underground nuclear tests UGT and earthquakes EQ. In an earlier program, infrasound signals from UGTs and EQs were collected at ranges of a few hundred kilometers, in the far-field. Analysis of these data revealed two parameters that had potential for discrimination purposes signal duration and wind-corrected amplitudes. These far-field differences should be present in the near-field signals as well. To study the near-field signals, we are using computational techniques based on modeled ground motions from UGTs and EQs. One is the closed form numerical integration of the Rayleigh integral RI, and the other is the application of a time-domain, finite-difference computational fluid dynamics CFD program, CAVEAT. This report summarizes recent progress in modeling these signals, showing comparisons of waveforms and power spectra from the two techniques. There is also a discussion of the effects of spatial and temporal zoning on the quality of the results. Application of Fourier techniques to the basic ground models is introduced as an analytic path to the radiation patterns of the ground-motion sources.

Descriptors:

• *RADIATION PATTERNS
• *COMPUTATIONAL FLUID DYNAMICS
• *INFRASOUND
• *GROUND MOTION
• *UNDERGROUND EXPLOSIONS
• EARTHQUAKES
• AMPLITUDE
• NEAR FIELD
• FOURIER ANALYSIS
• NUMERICAL INTEGRATION
• FINITE DIFFERENCE THEORY
• NUCLEAR EXPLOSION TESTING
• POWER SPECTRA
• SYMPOSIA
• MODELS

Subject Categories:

• Seismology
• Acoustics
• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE