Fig. 5From: Estimation of geomagnetically induced currents based on the measurement data of a transformer in a Japanese power network and geoelectric field observationsOccurrence number of 1-min values of geoelectric field data between 1987 and 2014 at the Memanbetsu Observatory and the CCDF of the values equal to or greater than 0.001 V/km. The dashed lines in the right panel show 95 % confidence interval of the fitting (solid line)Back to article page