Extreme geomagnetically induced currents

Progress in Earth and Planetary Science

Table 2 Historical hazardous events with SC-type transient GICs

Date	Record	Notes
24 March 1940	dH > 273 nT at KAK^a	Second largest storm (dH = −661 nT) at KAK
13 November 1960	dH = 220 nT at KAK^a	GLE10^b, 3rd largest 30 MeV SEP^c
4 August 1972	Shortest transit time, GIC^d	GLE24^f, 8th largest 30 MeV SEP^c
24 March 1991	dH = 202 nT^f, GIC^g	Largest 10 MeV SEP^h

^aMagnetometer observations at Kakioka (Araki 2014)
^bSteljes et al. (1961)
^cCliver and Svalgaard (2004)
^dLanzerotti (1983)
^e http://neutronm.bartol.udel.edu/~pyle/GLE_List.txt (GLE stands for the ground level enhancement of neutron monitor counting rate caused by the most energetic SEP)
^fAraki (1997)
^gKappenman (2003)
^h http://umbra.nascom.nasa.gov/SEP/