Figure 2
From: Preseismic atmospheric radon anomaly associated with 2018 Northern Osaka earthquake
Cumulative earthquake (Mj > 1.0) numbers in the epicentral region of the 2018 Northern Osaka earthquake. The regression line was drawn with the data (open black circles) in the normal period, and the standard deviation (σ) of the vertical fluctuation of the value with respect to the regression line was obtained. The area between + 3σ and − 3σ is shown in the grey area. Areas 1 and 2 are shown in Fig. 1.
