Evidence for a geomagnetic jerk in 1990 across Europe

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. A new geomagnetic jerk seems to have appeared around 1990 and is clearly visible at a selec- tion of European magnetic observatories as a rapid and sudden change in the secular variation pattern. The comparison between all day and quiet day means for two different observatories, respectively at high and middle latitude, suggests that this phenomenon, as stated by many authors for the other jerks, could be generated by an internal source.