Abstract
In the analysis of dense instrument array data obtained by independent triggering and recording systems, it is inevitably necessary to understand the accuracy of the data. Such requirement is particularly severe when ground strains induced during earthquakes are evaluated from differential ground displacements at several observing points. Errors associated with numerical integration of acceleration records at low frequency range and difference of sensitivities between instruments are likely to develop unrealistic ground strains. This paper presents experimental analysis on the effect of lower cut-off frequency of instrument correction filter, number of bits of AD converter and its sampling interval on accuracy of calculated displacement. And reliability of relative displacements evaluated from the records by plural instruments is also presented.
