scholarly journals Application of multichannel Wiener filters to the suppression of ambient seismic noise in passive seismic arrays

2008 ◽  
Vol 27 (2) ◽  
pp. 232-238 ◽  
Author(s):  
J. Wang ◽  
F. Tilmann ◽  
R. S. White ◽  
H. Soosalu ◽  
P. Bordoni
Keyword(s):  
Seismic Noise ◽  
Ambient Seismic Noise ◽  
Seismic Arrays ◽  
Wiener Filters ◽  
Passive Seismic

Wavefield reconstruction inversion for ambient seismic noise

2020 ◽  
Author(s):  
Sjoerd A.L. de Ridder ◽  
James R. Maddison ◽  
Ali Shaiban ◽  
Andrew Curtis
Keyword(s):  
Seismic Noise ◽  
Waveform Inversion ◽  
Irregular Sampling ◽  
Ambient Seismic Noise ◽  
Seismic Arrays ◽  
Temporal Relationships ◽  
Elastic Data ◽  
Passive Seismic ◽  
Noise Data ◽  
Estimate Dispersion

<p>With the advent of large and dense seismic arrays, there is an opportunity for novel inversion methods that exploit the information captured by stations in close proximity to each other. Estimating surface waves dispersion is an interest for many geophysical applications using both active and passive seismic data. We present an inversion scheme that exploits the spatial and temporal relationships of the Helmholtz equation to estimate dispersion relations directly from surface wave ambient noise data, while reconstructing the full wavefield in space and frequency. The scheme is a PDE constrained inverse problem in which we jointly estimate the state and parameter spaces of the seismic wavefield. Key to the application on ambient seismic noise recordings is to remove the boundary conditions from the PDE constraint, which renders a conventional waveform inversion formulation singular. With synthetic acoustic and elastic data examples we show that using a variable projection scheme, we can iteratively update an initial estimate of the medium parameters and recover an estimate for the true underlying velocity field. Our examples show that the we can reconstruct the full wavefield even in the case of strong aliasing and irregular sampling. This works forms the basis for a new approach to inverting ambient seismic noise using large and dense seismic arrays.</p>

On bias and noise in passive seismic data from finite circular array data processed using SPAC methods

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. V153-V162 ◽  
Author(s):  
Michael W. Asten
Keyword(s):  
Seismic Data ◽  
Seismic Noise ◽  
Imaginary Component ◽  
Empirical Measure ◽  
Restricted Range ◽  
Circular Array ◽  
Spatial Averaging ◽  
Seismic Arrays ◽  
Spectral Estimates ◽  
Passive Seismic

The finite nature of typical small seismic arrays used in conjunction with spatial autocorrelation (SPAC) processing for observing the microtremor wavefield causes predictable perturbations of the SPAC spectrum when sources of seismic noise are confined to a restricted range of azimuths. Such perturbations are especially evident at higher frequencies where wavelengths are on the order of the array radius. The effects are readily modeled and show that the triangular array geometries commonly used for microtremor studies require azimuthal distributions of wave energy on the order of [Formula: see text] or greater to have a high probability of being free of such perturbations. The imaginary component of the SPAC spectrum, which is ideally zero for a sufficiently dense circular array and/or a sufficiently isotropic wavefield, is in practice often nonzero and provides three quality-control indicators: (1) an indication of insufficient spatial averaging, (2) an empirical measure of the level of statistical uncertainty in SPAC spectral estimates, and (3) an indication of departures from plane-wave stationarity of the seismic noise wavefield.

scholarly journals Ambient Seismic Noise and Microseismicity Monitoring of a Prone-To-Fall Quartzite Tower (Ormea, NW Italy)

2021 ◽  
Vol 13 (9) ◽  
pp. 1664
Author(s):  
Chiara Colombero ◽  
Alberto Godio ◽  
Denis Jongmans
Keyword(s):  
Seismic Noise ◽  
Seismic Velocity ◽  
Seismic Monitoring ◽  
Geometric Constraints ◽  
Ambient Seismic Noise ◽  
Clear Correlation ◽  
3D Numerical Modeling ◽  
Permanent Displacement ◽  
Resonance Frequencies ◽  
Passive Seismic

Remote sensing techniques are leading methodologies for landslide characterization and monitoring. However, they may be limited in highly vegetated areas and do not allow for continuously tracking the evolution to failure in an early warning perspective. Alternative or complementary methods should be designed for potentially unstable sites in these environments. The results of a six-month passive seismic monitoring experiment on a prone-to-fall quartzite tower are here presented. Ambient seismic noise and microseismicity analyses were carried out on the continuously recorded seismic traces to characterize site stability and monitor its possible irreversible and reversible modifications driven by meteorological factors, in comparison with displacement measured on site. No irreversible modifications in the measured seismic parameters (i.e., natural resonance frequencies of the tower, seismic velocity changes, rupture-related microseismic signals) were detected in the monitored period, and no permanent displacement was observed at the tower top. Results highlighted, however, a strong temperature control on these parameters and unusual preferential vibration directions with respect to the literature case studies on nearly 2D rock columns, likely due the tower geometric constraints, as confirmed by 3D numerical modeling. A clear correlation with the tower displacement rate was found in the results, supporting the suitability of passive seismic monitoring systems for site characterization and early waning purposes.

Suppression of ambient seismic noise in 2D arrays using multichannel Wiener filters

2007 ◽  
Author(s):  
J. Wang ◽  
F. Tilmann ◽  
R. S. White ◽  
H. Soosalu ◽  
P. Bordoni
Keyword(s):  
Seismic Noise ◽  
Ambient Seismic Noise ◽  
Wiener Filters ◽  
2D Arrays
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