Authors
Yasuhiro Minamoto
Kakioka Magnetic Observatory, Japan Meteorological Agency, Kakioka 595 Ishioka-shi, Ibaraki, Japan
Nobuyuki Kumasaka
Kakioka Magnetic Observatory, Japan Meteorological Agency, Kakioka 595 Ishioka-shi, Ibaraki, Japan
Toshiaki Mishima
Kakioka Magnetic Observatory, Japan Meteorological Agency, Kakioka 595 Ishioka-shi, Ibaraki, Japan
Takeshi Oowada
Kakioka Magnetic Observatory, Japan Meteorological Agency, Kakioka 595 Ishioka-shi, Ibaraki, Japan
Takashi Okawa
Matsushiro Seismological Observatory, Japan Meteorological Agency, Nishijo 3511, Matsushiro-machi, Nagano-shi, Nagano-ken, Japan
