History of Kakioka Magnetic Observatory

History of Geo- and Space Sciences

article

Ikuko Fujii¹  Shingo Nagamachi² 

[1] Meteorological College;Kakioka Magnetic Observatory

DOI  :  10.5194/hgss-13-147-2022

学科分类：工业工程学

来源: Copernicus Publications

【 摘 要 】

Kakioka Magnetic Observatory (KMO) was founded in 1913 bythe Central Meteorological Observatory (CMO, later the Japan Meteorological Agency) as a successor to Tokyo Magnetic Observatory. Kakioka was a village 70 km north of Tokyo and was selected to escape from tram noise in Tokyo. At first, it was an unstaffed observatory only for geomagnetic field observation. Then, the Great Kanto Earthquake in 1923 changed the fate ofKMO because the earthquake severely damaged the CMO in Tokyo, and recording papers of KMO were lost. KMO was staffed in 1924 and was redesigned as an institute for geophysics rather than geomagnetism. KMO operated a variety ofobservations, such as the atmospheric electric field, the geoelectric field, the seismicity, the air temperature, the wind velocity, the sunspot andsolar prominence as well as the geomagnetic field, by the 1940s. In addition, research activity flourished with the leadership of the first director, Shuichi Imamichi. After World War II was over in 1945, KMO formed anetwork of observatories in Japan by founding several branch observatoriesoriginally for geoelectric field observation. Two branch observatories at Memambetsu and Kanoya survived, with geomagnetic field observation added in the International Geophysical Year project (1957–1958). Efforts in development of instruments for geomagnetic absolute measurement and systems of high-sampling recordings in the 1950s to 1970s resulted in the development of the Kakioka Automatic Standard Magnetometer (KASMMER) system in1972. KASMMER measured the geomagnetic field every 3 s at the highest standard in the world in digital form, giving 1 min digital values of the geomagnetic field available. This system has been updated, andthe high-sampling technology was applied to geoelectric field observation and atmospheric electric field observation. Later, addinggeomagnetic field observation at Chichijima in 1971, KMO established a unique electric and magnetic observation network at Kakioka, Memambetsu,Kanoya and Chichijima and provided precise and high-speed sampling data(1 min, 1 and 0.1 s values) by 2001. On the other hand, KMO graduallyterminated or automated their observations and reduced their staff in the last several decades following the government's reform policy. The two branchobservatories at Memambetsu and Kanoya were unstaffed in 2011, and the atmospheric electric field at Memambetsu was terminated at that time. Thegeoelectric field observations at Kakioka, Memambetsu and Kanoya wereterminated in 2021 as well as the atmospheric electric field at Kakioka. KMOfocuses on geomagnetic observation for now and puts efforts into total force observation at volcanoes and the digitization of historic analogdata.

【 授权许可】

CC BY