1. A method of performing seismic interferometry to obtain information related to subsurface structure, said method comprising: positioning a plurality of seismic receivers to receive seismic waves, wherein said positioning includes arranging at least a portion of the plurality of seismic receivers in an array within an area associated with a location of a virtual source for seismic interferometry; using at least one of the seismic receivers as a secondary location receiver for seismic interferometry; recording a time series of seismic waves incident on each seismic receiver of the array and on the secondary location receiver; and modifying a directionality function of the virtual source for seismic interferometry, wherein said modifying involves combining at least two of the time series from the seismic receivers included in the array.