Estimation of geomagnetically induced currents based on the measurement data of a transformer in a Japanese power network and geoelectric field observations

Earth, Planets and Space

Table 2 Largest geoelectric fields observed between 1958 and 2014 at the Memanbetsu Observatory

Number	Date and time (UT)	Max. \|E\| of 1-min data (V/km)	Geomagnetic disturbances at Memanbetsu
1	13 March 1989 at 21:58	0.184	SC storm (max. ∆H = 747 nT)
2	8 November 1991 at 22:17	0.137	SC storm (max. ∆H = 392 nT)
3	29 October 2003 at 19:54	0.123	SC storm (max. ∆H = 513 nT)
4	30 October 2003 at 19:54	0.120	SC storm (max. ∆H = 467 nT)
5	14 March 1989 at 00:03	0.115	SC storm (max. ∆H = 747 nT)
6	15 July 2000 at 21:36	0.115	SC storm (max. ∆H = 520 nT)
7	24 March 1991 at 04:02	0.115	SC storm (max. ∆ > 467 nT)
8	6 November 2001 at 02:02	0.104	SC storm (max. ∆H = 338 nT)