Active doublet method for measuring small changes in physical properties
- Los Alamos, NM
- Santa Fe, NM
Small changes in material properties of a work piece are detected by measuring small changes in elastic wave velocity and attenuation within a work piece. Active, repeatable source generate coda wave responses from a work piece, where the coda wave responses are temporally displaced. By analyzing progressive relative phase and amplitude changes between the coda wave responses as a function of elapsed time, accurate determinations of velocity and attenuation changes are made. Thus, a small change in velocity occurring within a sample region during the time periods between excitation origin times (herein called "doublets") will produce a relative delay that changes with elapsed time over some portion of the scattered waves. This trend of changing delay is easier to detect than an isolated delay based on a single arrival and provides a direct measure of elastic wave velocity changes arising from changed material properties of the work piece.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM
- DOE Contract Number:
- W-7405-ENG-36
- Assignee:
- United States of America as represented by United States (Washington, DC)
- Patent Number(s):
- US 5369997
- OSTI ID:
- 869629
- Country of Publication:
- United States
- Language:
- English
Monitoring velocity variations in the crust using earthquake doublets: An application to the Calaveras Fault, California
|
journal | July 1984 |
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