Matched filtering for the seismic moment tensor

Abstract

By a process of matched filtering it is possible to deconvolve a small number of acceleration or strain records for the moment rate tensor of a seismic source. Theoretically, one horizontal accelerometer (or strain meter) or two vertical accelerometers is sufficient. Practically, five to ten records can be shown to suffice. Specifically, the mechanism of the Colombian event of July 31, 1970 can be retrieved from a sparse network of ten WWSSN vertical instruments.

Historical seismograms: Preserving an endangered species

“…We are helped in this respect by the fact that robust moment tensors can be obtained from relatively sparse datasets. Buland and Gilbert [9] showed that it is at least theoretically possible to invert a single, non-naturally rotated horizontal record into the full time history of the moment tensor, and Ekström et al [20] demonstrated that it was feasible to invert a static moment from a three-component record at a single digital broad-band station. Of course, the situation deteriorates when working with analog data (WWSSN or older), since the narrower response of the instruments acts as a de facto filter on the dataset and reduces its resolution.…”

Bias in the estimate of seismic moment tensor by the linear inversion method

“…The extension to surface waves has been proposed by a number of investigators (Buland & Gilbert 1976;McCowan 1976;Mendiguren 1977). This paper uses the frequency domain inversion proposed by Mendiguren instead of the time domain inversions of the other investigators.…”

“…In light of the evidence summarized by Aki (1967Aki ( , 1972 and Chouet, Aki & Tsujiura (1978), the step function assumption is valid for periods longer than 20s when the magnitude of the source is six or less.…”

“…The linear inversion of seismograms to recover the moment tensor (Dziewonski & Gilbert 1974; Buland & Gilbert 1976;McCowan 1976;Mendiguren 1977) has attracted great interest because it is general and much faster for determining the focal mechanism than the previous methods of trial and error search of source parameter space. Dziewonski & Gilbert determined the moment tensor of two deep shocks in South America by simple least squares inversion, which gives the moment tensor elements as a linear combination of real and imaginary parts of the Fourier transform of seismograms observed at many stations.…”

Source and Propagation Effects of Rayleigh Waves from Central Asian Earthquakes

“…The first application of the linear inversion was carried out by Dziewonski and Gilbert (1974) on free oscillation datasets for two deep shocks in South America. Extensions of this method to other datasets have been proposed by a number of investigators (Buland and Gilbert, 1976;McCowan, 1976;Mendiguren, 1977).…”