Geomagnetic Surveys by the Geospatial Information Authority of Japan and the Contribution of the Kakioka Magnetic Observatory

The Geospatial Information Authority of Japan (GSI) has been conducting geomagnetic surveys in Japan since 1949 to clarify the geographical distribution of direction, intensity of the geomagnetic field, and their secular variations. Recently, we have carried out continuous observations at geodetic observatories and continuous geomagnetic stations and repetitive observations at several first-order geomagnetic stations. The results of the surveys, “geomagnetic charts”, have been published every 10 years. In 2011, GSI released the newest geomagnetic charts for the epoch 2010.0 created by adopting a new spatial-temporal model. This model needs continuous data of good quality. In addition to the GSI geodetic observatories, the Kakioka Magnetic Observatory, which has been conducting high-quality and stable observations for 100 years, makes a large contribution.