Possibly causes of low resistivity zones along an active fault: a case study at the Atera Fault

sugitani yasuhiro; Tada-nori Goto

Presentation information

[E] Oral

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

[S-EM12] Electric, magnetic and electromagnetic survey technologies and scientific achievements

Sun. May 26, 2024 1:45 PM - 3:00 PM 304 (International Conference Hall, Makuhari Messe)

convener:Tada-nori Goto(Graduate School of Science, University of Hyogo), Yoshiya Usui(Earthquake Research Institute, the University of Tokyo), Yuguo Li(Ocean University of China), Wiebke Heise(GNS Science, PO Box 30368, Lower Hutt, New Zealand), Chairperson:Wiebke Heise(GNS Science, PO Box 30368, Lower Hutt, New Zealand), Koki Aizawa(Institute of Seismology and Volcanology, Faculty of Sciences, Kyushu University), Shogo Komori(National Institute of Advanced Industrial Science and Technology)

2:30 PM - 2:45 PM

[SEM12-14] Possibly causes of low resistivity zones along an active fault: a case study at the Atera Fault

sugitani yasuhiro¹, *Tada-nori Goto¹ (1.Graduate School of Science, University of Hyogo)

Keywords:Active Fault, Magnetic Susceptibility, Resistivity

Along many active faults, the fault core and damage zone (so called "fault fracture zone") exhibit low resistivity. The reasons for the low resistivity along the fault are follows; 1) high water content of the rock due to fracturing, and 2) clay minerals in and around the fault core. Both causes are produced by the fault movement. However, few researches have progressed on whether pore water or clay minerals are the dominant cause of the low resistivity. In this study, we try to discuss the major causes of low resistivity along faults by measuring physical properties and identifying minerals at active fault outcrops. Our target is the Atera Fault located in Gifu Prefecture, Japan. Here, the active fault outcrops have been investigated in detail (Niwa et al., 2016; Zwingmann et al., 2024). In addition to this information, we conducted 1) measurements of magnetic susceptibility, 2) XRD analysis, and 3) resistivity measurements by DC resistivity survey. In this presentation, these results are introduced, and then discuss and consider the factors currently considered appropriate for low resistivity along the fault.