Figure 3
From: Preseismic atmospheric radon anomaly associated with 2018 Northern Osaka earthquake
Time series in the atmospheric radon concentration. (a) Radon concentration; grey line represents a sinusoidal regression curve (Eq. (1)) that best fits the radon concentration data (open black circles) during the normal period. Black, red, and blue represent data during normal, preseismic, and postseismic periods, respectively. Small dots are raw data. (b) Residual radon variation CV; The area between + 3σ and − 3σ is shown in the grey area in (b).
