Imaging of a serpentinite complex in the Kamuikotan Zone, northern Japan, from magnetotelluric soundings

Earth, Planets and Space

卷:73

Shusaku Yamazaki¹  Kenji Okazaki¹  Hiroshi Ichihara²  Toru Mogi²  Hideyuki Satoh³  Masakazu Fujii⁴  Yusuke Yamaya⁵  Noriko Tada⁶  Toshihiro Uchida⁷ 

[1] Civil Engineering Research Institute for Cold Region;

[2] Earthquake and Volcano Research Center, Graduate School of Environmental Studies, Nagoya University;

[3] Institute of Seismology and Volcanology, Graduate School of Science, Hokkaido University;

[4] National Institute of Polar Research;

[5] Renewable Energy Research Center, National Institute of Advanced Industrial Science and Technology (AIST);

[6] Research Institute for Marine Geodynamics, Japan Agency for Marin-Earth Science and Technology;

[7] The Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST);

关键词: Magnetotelluric method;    Electrical conductivity;    Resistivity;    Serpentinite;    Slow earthquake;    Slow slip;   

DOI  :  10.1186/s40623-021-01482-5

来源: DOAJ

【 摘 要 】

Abstract We conducted magnetotelluric measurements to investigate a large serpentinite complex in the northern Kamuikotan Zone that intruded a Cretaceous–Paleocene forearc sedimentary sequence. The resistivity model we derived by three-dimensional inversion clearly shows a low-resistivity zone beneath the outcrop of the serpentinite complex. We interpret the low-resistivity zone to represent aqueous pore fluid within a serpentinite mélange derived from the subducting Pacific plate or mantle wedge. Previous geological studies in the area have shown that the serpentinite mélange had uplifted during the early Pleistocene. They indicate that the ultramafic rocks and aqueous fluids have continued to rise in the area. The uplifting serpentinite body might have formed a zone enriched in pore fluid that promoted the occurrence of a previously identified intra-plate slow slip event. These results demonstrate the important role of fluid transport during tectonic processes related to uplift in subduction zones.

【 授权许可】

Unknown