Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

S (Solid Earth Sciences ) » S-EM Earth's Electromagnetism

[S-EM19] Electromagnetic Induction in the Earth and Planetary Interiors, and Tectono-Electromagnetism

Mon. May 27, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Koki Aizawa(Institute of Seismology and Volcanology, Faculty of Sciences, Kyushu University), Tetsuo Matsuno(Kobe Ocean Bottom Exploration Center, Kobe University)

[SEM19-P01] Effects of absolute humidity on contact resistance between dry rock sample surface and electrodes

*Takeshi Suzuki1, Ryokei Yoshimura2, Ken'ichi Yamazaki2, Naoto Oshiman2 (1.Graduate School of Science, Kyoto University, 2.Disaster Prevention Research Institute, Kyoto University)

Keywords:contact resistance, atmospheric Moisture, absolute humidity, contact area, conductive epoxy, granite

Resistivity measurements of rock under various conditions are essential for accurately interpreting geoelectromagnetic survey results. However, the contact resistance between the rock sample and measuring electrodes is a problem in measuring the resistivity of a rock sample. Because the measurement of high contact resistance on the dry rock surface is particularly difficult, its characteristics have not been well studied.
In order to investigate the characteristics of contact resistance, we have developed a measurement method of high contact resistance. By using the method, we measured high contact resistance between the dry granite surface and the electrode made of conductive epoxy. Considering the interaction between atmospheric moisture and rock samples, the contact resistance was repeatedly measured under different humidity conditions.
We confirmed the contact resistance decreased with increasing absolute humidity. A clear relationship exists between contact resistance and absolute humidity, and the relationship was approximated by an exponential function. This result suggests that increasing the contact area between the electrode and the rock surface with rising humidity. Moisture in the atmosphere may have caused improvement of contact condition by filling the microscopic gap in the contact surface.