Time variations of the characteristics of the LSTID detected by the HF-INT at Dourbes, Belgium, for April 23, 2023. The top plot depicts the activity levels of LSTIDs (green, yellow, orange, red, and magenta for Insignificant, Weak, Moderate, Strong, and Very Strong activity, respectively). The middle plot depicts the dominant period (black diamonds) and SEC (green diamonds), and bottom plots depict the magnitude of the velocity (red diamonds) and azimuth direction (blue squares) of propagation of the detected LSTID.