Passive seismic - SPAC (Spatial Autocorrelation Method)

It is a passive seismic method where micro-tremors are recorded through a set of equidistant stations, generally arranged in triangular arrangements, forming pairs of stations with variable azimuths. The data processing is carried out through spatial autocorrelations where it is possible to estimate the surface waves phase velocity, regardless of their propagation direction with more robust results than ReMi. These seismic data can be processed with the F-K technique (“Frequency-Wavenumber Domain”) that allows transforming these records to the Frequency-Wave Number domain to filter the noise in the signal more quickly.