Introducing noisi: a Python tool for ambient noise cross-correlation modeling and noise source inversion

Cross-correlation imaging of ambient noise sources

S U M M A R Y We develop and apply a novel technique to image ambient seismic noise sources. It is based on measurements of cross-correlation asymmetry defined as the logarithmic energy ratio of the causal and anticausal branches of the cross-correlation function. A possible application of this technique is to account for the distribution of noise sources, a problem which currently poses obstac...

Microseism source direction from noise cross-correlation

S U M M A R Y Inhomogeneous noise sources surrounding stations produce asymmetric amplitudes in crosscorrelation functions that yield preferential source directions. Here we show that preprocessing biases the dominant source direction estimate towards the source producing long-duration signals by down-weighting high-amplitude signals. Tests with both synthetic data and observations show that co...

Compressive geoacoustic inversion using ambient noise.

Surface generated ambient noise can be used to infer sediment properties. Here, a passive geoacoustic inversion method that uses noise recorded by a drifting vertical array is adopted. The array is steered using beamforming to compute the noise arriving at the array from various directions. This information is used in two different ways: Coherently (cross-correlation of upward/downward propagat...

Ambient noise cross correlation in free space: theoretical approach.

It has been experimentally demonstrated that the Green's function between two points could be recovered using the cross-correlation function of the ambient noise measured at these two points. This paper investigates the theory behind this result in the simple case of a homogeneous medium with attenuation.

Bayesian Ambient Noise Inversion for Geoacoustic Uncertainty Estimation: Final report