Guralp-systems ART Manual do Utilizador descarregar pdf (Página 44)

ART

record. Comparing these two spectra enables a choice of the

high-pass cut-off frequency to be made.

The figure above shows an example where a cut-off frequency

of about 1.5Hz is suggested by comparing the two spectra

because for lower frequencies the signal-to-noise ratio is quite

low.

A sub-figure underneath can be requested in the ‘Options’

menu at the top of the figure to show the signal-to-noise

spectral ratio computed using the Fourier amplitude spectra of

the pre-event portion (as an estimate of the noise) and the

remainder of the record (as an estimate of the signal).

Also shown in this figure (if the ‘Display metadata’ option is

selected in the ‘Options’ window) are the basic earthquake,

waveform and station metadata of the selected time-history.

Multiple time-histories selected

Clicking on this button when multiple time-histories have been

selected calculates and plots the Fourier amplitude spectra of

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Guralp-systems ART Manual do Utilizador Página 44