Figure 3

Microseism amplitude maps. Spatial distribution of the median values of RMS amplitude time series in the bands 2.5–5 s (short period secondary microseism; a,d,g), 5–10 s (secondary microseism; b,e,h) and 13–20 s (primary microseism; c,f,i), obtained by applying a triangulation-based natural neighbour interpolation⁵¹. The plots (a–c) were obtained by taking into account the whole year, while the plots (d–f) and (g–i) are focused on the periods with the strongest (February–April) and weakest (October–December) microseism, respectively. The black dots indicate the locations of the considered stations. It has to be noted that the color scale used for primary microseism 13–20 s (c,f,i) is different from the color scales used for secondary microseism 5–10 s (b,e,h) and short period secondary microseism 2.5–5 s (a,d,g).