Fig. 3From: Influence of geomagnetic storms on the quality of magnetotelluric impedanceVariations in the Hx component of site 163 and the Dst index. a Shows the variation in the Hx component. b Shows the first derivative of the Hx component. c Shows the variation in the Dst index. d Shows the first derivative of the Dst index's absolute value; the red dashed line denotes 1.5σ (σ is the standard deviation). The horizontal axis denotes the time in UTC. The shadow in red represents the data in the storm periodBack to article page