Electric Signals on and under the Ground Surface Induced by Seismic Waves
We constructed three observation sites in northeastern Japan (Honjo, Kyowa, and Sennan) with condenser-type large plate electrodes (4 × 4 m2) as sensors supported 4 m above the ground and with pairs of reference electrodes buried vertically at 0.5 m and 2.5 m depth (with a ground velocity sensor at...
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| Format: | Article |
| Language: | English |
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Wiley
2012-01-01
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| Series: | International Journal of Geophysics |
| Online Access: | http://dx.doi.org/10.1155/2012/270809 |
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| author | Akihiro Takeuchi Kan Okubo Nobunao Takeuchi |
| author_facet | Akihiro Takeuchi Kan Okubo Nobunao Takeuchi |
| author_sort | Akihiro Takeuchi |
| collection | DOAJ |
| description | We constructed three observation sites in northeastern Japan (Honjo, Kyowa, and Sennan) with condenser-type large plate electrodes (4 × 4 m2) as sensors supported 4 m above the ground and with pairs of reference electrodes buried vertically at 0.5 m and 2.5 m depth (with a ground velocity sensor at Sennan only). Electrical signals of an earthquake (M6.3) in northeastern Japan were detected simultaneously with seismic waves. Their waveforms were damped oscillations, with greatly differing signal amplitudes among sites. Good positive correlation was found between the amplitudes of signals detected by all electrodes. We propose a signal generation model: seismic acceleration vertically shook pore water in the topsoil, generating the vertical streaming potential between the upper unsaturated water zone and the lower saturated water zone. Maximum electric earth potential difference was observed when one electrode was in the saturated water zone, and the other was within the unsaturated water zone, but not when the electrodes were in the saturated water zone. The streaming potential formed a charge on the ground surface, generating a vertical atmospheric electric field. The large plate electrode detected electric signals related to electric potential differences between the electrode and the ground surface. |
| format | Article |
| id | doaj-art-eb281089fe7a4736aae0237f87f6a648 |
| institution | Kabale University |
| issn | 1687-885X 1687-8868 |
| language | English |
| publishDate | 2012-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Geophysics |
| spelling | doaj-art-eb281089fe7a4736aae0237f87f6a6482025-02-03T01:29:00ZengWileyInternational Journal of Geophysics1687-885X1687-88682012-01-01201210.1155/2012/270809270809Electric Signals on and under the Ground Surface Induced by Seismic WavesAkihiro Takeuchi0Kan Okubo1Nobunao Takeuchi2Earthquake Prediction Research Center, Institute of Oceanic Research and Development, Tokai University, 3-20-1 Orido, Shimizu-ku, Shizuoka 424-8610, JapanDivision of Information and Communications Systems Engineering, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino 191-0065, JapanResearch Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-8578, JapanWe constructed three observation sites in northeastern Japan (Honjo, Kyowa, and Sennan) with condenser-type large plate electrodes (4 × 4 m2) as sensors supported 4 m above the ground and with pairs of reference electrodes buried vertically at 0.5 m and 2.5 m depth (with a ground velocity sensor at Sennan only). Electrical signals of an earthquake (M6.3) in northeastern Japan were detected simultaneously with seismic waves. Their waveforms were damped oscillations, with greatly differing signal amplitudes among sites. Good positive correlation was found between the amplitudes of signals detected by all electrodes. We propose a signal generation model: seismic acceleration vertically shook pore water in the topsoil, generating the vertical streaming potential between the upper unsaturated water zone and the lower saturated water zone. Maximum electric earth potential difference was observed when one electrode was in the saturated water zone, and the other was within the unsaturated water zone, but not when the electrodes were in the saturated water zone. The streaming potential formed a charge on the ground surface, generating a vertical atmospheric electric field. The large plate electrode detected electric signals related to electric potential differences between the electrode and the ground surface.http://dx.doi.org/10.1155/2012/270809 |
| spellingShingle | Akihiro Takeuchi Kan Okubo Nobunao Takeuchi Electric Signals on and under the Ground Surface Induced by Seismic Waves International Journal of Geophysics |
| title | Electric Signals on and under the Ground Surface Induced by Seismic Waves |
| title_full | Electric Signals on and under the Ground Surface Induced by Seismic Waves |
| title_fullStr | Electric Signals on and under the Ground Surface Induced by Seismic Waves |
| title_full_unstemmed | Electric Signals on and under the Ground Surface Induced by Seismic Waves |
| title_short | Electric Signals on and under the Ground Surface Induced by Seismic Waves |
| title_sort | electric signals on and under the ground surface induced by seismic waves |
| url | http://dx.doi.org/10.1155/2012/270809 |
| work_keys_str_mv | AT akihirotakeuchi electricsignalsonandunderthegroundsurfaceinducedbyseismicwaves AT kanokubo electricsignalsonandunderthegroundsurfaceinducedbyseismicwaves AT nobunaotakeuchi electricsignalsonandunderthegroundsurfaceinducedbyseismicwaves |