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The seismic noise wavefield is not diffuse.
1Dipartimento di Fisica, Settore di Geofisica, Università di Bologna, Bologna, Italy. Francesco.Mulargia@unibo.it
The Journal of the Acoustical Society of America
|April 17, 2012
Summary
Passive seismology relies on diffuse acoustics, but seismic noise is not a diffuse wavefield. This finding does not impact passive seismic imaging capabilities.
Area of Science:
- Geophysics
- Seismology
- Acoustics
Background:
- Passive seismology is increasingly utilized, often supported by diffuse acoustics theory.
- Concerns exist regarding the applicability of diffuse field theory to seismic noise.
- Seismic noise characteristics are crucial for understanding passive imaging methods.
Purpose of the Study:
- To develop and apply a procedure for assessing the diffuse field paradigm's applicability to seismic noise.
- To test seismic noise for azimuthal isotropy and spatial homogeneity.
- To determine if seismic noise wavefields conform to the diffuse field model.
Main Methods:
- A novel procedure was developed to test wavefield properties.
- The procedure involved assessing azimuthal isotropy and spatial homogeneity.
- Seismic noise data from 65 diverse sites were analyzed using instantaneous oscillation vectors.
Main Results:
- The hypothesis of azimuthal isotropy was rejected for all analyzed seismic noise data.
- Azimuthal anisotropy indicates that seismic noise is not a diffuse wavefield.
- The spatial homogeneity test was rendered unnecessary due to the rejection of isotropy.
Conclusions:
- Seismic noise wavefields are demonstrably not diffuse.
- The non-diffuse nature of seismic noise does not preclude its use in passive seismic imaging.
- Passive seismic imaging remains effective even with non-diffuse wavefields.
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