Figure 11.
Two displacement analysis plots compare Y O L O, T E M A, and tracker measurements. The left plot presents displacement in millimetre on the vertical axis ranging from minus 2.5 to 2.0 millimetre and time in second on the horizontal axis ranging from 0.1 to 0.3 second. All three signals oscillate around zero with similar waveforms and closely overlapping peaks and troughs. Oscillation amplitudes increase towards the middle of the time range, reaching positive peaks near 1.5 millimetre and negative troughs near minus 2.0 millimetre between approximately 0.18 and 0.26 second. The tracker signal presents slightly larger peak variations than the Y O L O and T E M A signals in several oscillation cycles. The right plot presents amplitude in millimetre on a logarithmic vertical scale ranging from 0.001 to 1.0 millimetre and frequency in hertz on the horizontal axis ranging from 0 to 200 hertz. All three spectra contain dominant peaks near 80 to 90 hertz with amplitudes slightly above 0.1 millimetre. Smaller amplitude variations are distributed across the remaining frequency range, with amplitudes decreasing above approximately 100 hertz.Comparison of seismic displacement signals analysed by YOLO, Tracker, and TEMA Motion: (a) time histories, and (b) FFT