Fig. 8From: DigitSeis: software to extract time series from analogue seismogramsAn example of a Develocorder-type recording. Three-component strong-motion recordings of the Ferndale, CA earthquake, on December 21, 1954. There are three time channels, at the top, bottom, and between top and middle traces. The middle time channel indicates that a pair of line and gap covers 0.5 secondBack to article page