The development of a measuring system for the electromagnetic phenomena caused by volcanic activity of Mount Sakurajima

In order to examine the relationship between volcanic explosions and electromagnetic phenomena, we constructed the continuous extremely low frequency (ELF) band measuring system, which is composed of geoelectric potential differences (GPDs) and geomagnetic fields (GF's) at the foot of Mt. Sakurajima, Kyushu Island, Japan. The results of the measurements show that the measuring system is able to measure the natural phenomena properly and the GPDs in the horizontal direction are observed which are assumed to be associated with the volcanic activity of Mt. Sakurajima when the seismometer was active.