Low-latitude infrasonics associated with geomagnetic activity

Summary. Certain associated fluctuations in geomagnetic records and infrasonic pressure variations at ground level noted at Hyderabad and Delhi are discussed with the help of simultaneous records taken during 1980. Typical infrasound signals are noted, apparently generated by the magnetic substorms in the auroral zones and travelling down to near tropical latitudes with speeds in the range of 400–500m s^-1. Characteristic signatures in infrasound records, corresponding to SSCs and storm time fluctuations are also noted, but only when substorms are associated with the storms.