Answers are grounded in this paper and cite their sources.
A matched three‐component seismograph system operating with pendulum period of 30 sec and galvanometer period of 90 sec is described. As a result of increased sensitivity for periods greater than 20 sec, seismograms from these instruments contain information not previously available.
No takes yet. Share an insight, caveat, or question.
Press et al. (1958) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: