2001 Fiscal Year Final Research Report Summary
Study on Electromagnetic wave environment: and its propagation characteristics in the earth
| Project/Area Number |
12831008
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Institution | Kyoto Sangyou University |
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Principal Investigator |
TSUTUSI Minoru Kyoto Sangyo University, Information and Communication Science, Professor, 工学部, 教授 (10026172)
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| Project Period (FY) |
2000 – 2001
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| Keywords | EM environment in the Earth / EM propagation in the Earth / EM sensors / Electrical parameters in the Earth / Generation of Earth-origin EM / Seismological effects |
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| Research Abstract |
Using a specific deep bore-hole, we have been measuring wave electromagnetic (EM) behavior in the earth.
The data acquisition and analysis system we developed can make it possible to clearly show wave behaviors. Furthermore, we developed another system for measuring electric parameters in the earth. On the basis of such the developed systems, we have been continuously observing and examining the noise circumstances in the both regions, above and under the ground.
(1) We detected strong electric pulse swarms above and under the ground since June and decaying in mid-September in 2000. From their analysis, we found that the intensity of the pulses detected above the ground was weaker than those in the earth. The weaker intensity of the pulses detected above the ground is a conclusive evidence of leakage of the earth-origin electric pulses.
(2) We also found lower frequency cutoffs in frequency spectra of the earth-origin electric pulses, which suggests the existence of a kind of wave-guide in the earth. From the cutoff frequency, we have estimated the depth of the bottom conductive layer as a wave-guide boundary in the earth. The estimated depth is consistent with that derived from the analysis of geomagnetic field.
(3) It is very interesting that the period in detecting strong electric pulse swarms was consistent with the 1 cm movement of Japan plate, which was reported by the Geographical Survey Institute Ministry of Land, Infrastructure and Transport, Japan.
(4) We have obtained depth dependencies of the specific dielectric coefficient and specific conductivity in the earth crust.
(5) We also found that the background electric noises are monotonically increasing in accordance with the depth in the earth crust.
These results are going to be published in the XXVIIth URSI General Assembly in Netherlands, August 2002.
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Research Products
(4 results)
