Frequency extrapolation to enhance the deconvolution of transmitted seismic waves

Abstract

We investigate the enhanced deconvolution of transmitted seismic waves from distant natural sources using autoregressive extrapolation (AR) and extended time-domain deconvolution. The amplitude spectrum of deconvolved seismograms is often restricted to a reduced frequency range from the use of a water table for the deconvolution. The attenuation effects on the teleseismic seismic waves also reduce the frequency content of the data. We compare the deconvolved spectra obtained from an AR-extended deconvolution (EARD) and an extended time-domain deconvolution (ETDD) technique for teleseismic waves. For EARD, we analyse the spectral content for the deconvolved spectra to differentiate between the domains of known and unknown spectral values. A prediction error filter is used to perform the autoregressive extrapolation to estimate the unknown spectral values. This procedure is applied on 1D and 2D synthetic data to test the approach. The EARD approach is then compared with the ETDD approach which applies an extended high-pass filter to the time-domain deconvolution approach. Both the EARD and ETDD approaches for extending the effective frequency range of the deconvolution results are then compared using observed teleseismic data recorded in southern India.