Various methods of processing ambient noise data and teleseismic coda waves, recorded by seismic arrays, have been developed by different groups. The main goal of these investigations is to locate endogenous sources of microseisms beneath the array (in the ambient noise case) or to detect scattering (in both cases). In the simplest processing scheme, semblance is used to measure the coherent energy exhibiting hyperbolic moveout arriving from sources (primary sources or scatterers) in the medium. The processing reveals some possible sources at depth, but the results are strongly influenced by surface sources. To eliminate the influence of these sources, a least-squares method in the frequency domain has been applied, but the method is hampered by the problem of estimating a source signal, which is required by the algorithm.