Fig. 3

Experiments of two-class classification in this study corresponding to Table 3. a Experiment-1: The experiment involved six tests that compared the signals from the source to the stations at the same area. b Experiments-2–5: These experiments considered sources from one area to stations in other areas. In total, there were twelve tests considered in Experiments-2–5. \({T}_{\text{A}}\), \({T}_{\text{B}}\), \({T}_{\text{C}}\), and \({T}_{\text{D}}\) represents the four classes of tremors in Areas A to D, while \({S}_{\text{A}}\), \({S}_{\text{B}}\), \({S}_{\text{C}}\), and \({S}_{\text{D}}\) represents the stations in each area. The names of stations are listed in Table 1