| A virtual source can be generated by cross-correlating the receiver at the virtual source location with all receivers that are active during the same time period. The correlation is over many segments of time. In the examples below data are correlated for a week ot time using one-hour chunks. The degree to which the virtual source resembles the Green's Function, depends on the origin the noise that energizes the corelations and the distribution of the scatterers. | ||
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| Example of a real source with Vibrators. Click on image to see movie. | Example of a virtual source. Click on image to see movie. | |
| The virtual source need not be within the array itself. Below we show examples where the virtual source is generated using SCSN stations. One of the advantages of distant sources is that the phase have a better chance to separate from each other. |
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| Example of a remote source using station DLA. Click on image to see movie. |