The analysis of geomagnetic data from magnetic observatories demonstrated the existence of very rapid changes. or jerks. in the secular variation. especially the occurrence of the well known geomagnetic jerks of 1969 and 1978. https://www.spidertattooz.com/RadioRA-3-Sunnata-Single-Pole-Multi-Location-Tap-Smart-Light-Switch-Neutral-Required-White/