HR: 1340h
AN: S33B-1316    [Abstracts]
TI: Observation of electromagnetic signals in an underground observation room
AU: * Watanabe, S
EM: m09b015@akita-pu.ac.jp
AF: Akita Prefectural University, Department of Electronic and Information Systems, 84-4 Tsuchiya-Ebinokuchi, Yurihonjo, 015-0055, Japan
AU: Okubo, K
EM: kanne@sd.tmu.ac.jp
AF: Tokyo Metropolitan University, Division of Information and Communications Systems Engineering, 6-6 Asahigaoka, Hino, 191-0065, Japan
AU: Takeuchi, A
EM: atakeuchi@akita-pu.ac.jp
AF: Akita Prefectural University, Department of Electronic and Information Systems, 84-4 Tsuchiya-Ebinokuchi, Yurihonjo, 015-0055, Japan
AU: Ishii, T
EM: jmr@hosokura.co.jp
AF: Hosokura Metal Mining Co. Ltd., 48 Nangoaramachi, Uguisuzawa, Kurihara, 989-5402, Japan
AU: Takeuchi, N
EM: ntake@akita-pu.ac.jp
AF: Akita Prefectural University, Department of Electronic and Information Systems, 84-4 Tsuchiya-Ebinokuchi, Yurihonjo, 015-0055, Japan
AB: We constructed an underground room to observe electromagnetic signals in the terrestrial environment associated with earthquake in 2004. Underground observation has an advantage; it is hardly influenced by the meteorological conditions and artificial noises. The observation room locates in the middle of a drift that penetrates the tuff and andesite bedrock, in Miyagi Prefecture, northeast Japan. This room is 1.5 km deep from the pithead and 70 m below the ground surface, and the room size is about 15 m x 12 m area with about 2.5 m height. In the observation room, we have observed the vertical electrostatic field, geomagnetic field, seismic wave, air ion concentration and static electricity on the wall, as well as the air pressure, air temperature and humidity. The observed data are stored in recorders with a GPS time stamp system, so that the time accuracy of 1 ms is assured. As a result, the normal signal levels of air ion concentration exhibit daily and seasonal changes slightly that can be explained by the air movement in the drift system and the earth tide effects. In addition, we often got anomalous signals when seismic waves arrived. In this presentation, we report the details of the underground observation system and some of the anomalous signals.
DE: 0694 Instruments and techniques
DE: 1500 GEOMAGNETISM AND PALEOMAGNETISM
DE: 3304 Atmospheric electricity
DE: 3389 Tides and planetary waves
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
SC: Seismology [S]
MN: 2007 Fall Meeting