Distribution of flares on the sun - Superactive regions and active zones of 1980-1985

The author analyzed coordinates of energetic solar flares observed with the hard X-ray burst spectrometer during the period from February 1980 through August 1985. A small number of 'superactive regions' produced the majority of the major flares during this period. There exist active zones, in which the flare occurrence rate is much higher. Two active zones are in the northern hemisphere, and two are in the southern hemisphere. The longitudinal separation of the two active zones in the same hemisphere is about 180 deg, but tha active zones of the southern hemisphere are misaligned from those of the northern hemisphere by about 80 deg. The rotation period of the active zones is 26.75 d. Active zones last several years or longer. There is a hint of active centers rotating at a period of 23.7 d.