Field-based description of near-surface crustal deformation in a high-strain shear zone; A Case study in southern Kyushu, Japan

Niwa, Masakazu; Shimada, Koji; Terusawa, Shuji*; Goto, Akira*; Nishiyama, Nariaki; Nakajima, Toru; Ishihara, Takanori; Hakoiwa, Hiroaki

Island Arc, 33(1), p.e12516_1 - e12516_16, 2024/02

https://doi.org/10.1111/iar.12516

To investigate the geological evidence of near-surface crustal deformations in a high-strain shear zone that has been geodetically identified but not associated with clear tectonic landforms, a fieldwork was conducted in E-W trending southern Kyushu high-strain shear zone, Japan. According to our study, an investigation based on the slip data from minor faults and the occurrences of fracture zones could help to identify a concealed fault that is small in terms of size to record tectonic landforms but can trigger large earthquakes.

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2023)

Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Fujita, Natsuko; Yokoyama, Tatsunori; Ogita, Yasuhiro; Fukuda, Shoma; Nakajima, Toru; Kagami, Saya; Ogata, Manabu; et al.

JAEA-Review 2023-017, 27 Pages, 2023/10

JAEA-Review-2023-017.pdf:0.94MB

This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2023. The objectives and contents in fiscal year 2023 are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.

In-operando distribution measurement of internal temperature and stress in lithium-ion battery

Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamamoto, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(5), p.345 - 353, 2023/10

https://doi.org/10.18957/rr.11.5.345

no abstracts in English

Chiral restoration of nucleons in neutron star matter; Studies based on a parity doublet model

Minamikawa, Takuya*; Gao, B.*; Kojo, Toru*; Harada, Masayasu*

Symmetry (Internet), 15(3), p.745_1 - 745_30, 2023/03

https://doi.org/10.3390/sym15030745

Attempts to detect thermal anomalies associated with slab-derived fluid activities based on low-temperature thermochronology

Sueoka, Shigeru; Iwano, Hideki*; Danhara, Toru*; Okamoto, Akira*; Tagami, Takahiro*

Fisshion, Torakku Nyusureta, (35), p.1 - 4, 2022/12

no abstracts in English

Evaluation of potential age standards for zircon (U-Th)/He thermochronometry; Results from further chronometric investigations

Fukuda, Shoma; Kohn, B. P.*; Sueoka, Shigeru; Danhara, Toru*; Iwano, Hideki*; Tagami, Takahiro*

Fisshion, Torakku Nyusureta, (35), p.7 - 10, 2022/12

In order to establish the age standard of zircon (U-Th)/He method, we performed zircon (U-Th)/He (hereinafter, ZHe) dating on 4 zircon samples. In this presentation, the Nohi rhyolite and the Mt. Wasso moonstone rhyolite as domestic samples, and Mt. Dromedary and OD-3 were also adopted as age standard zircons of fission-track and U-Pb methods. Consequently, regarding the ZHe age of the Nohi rhyolite indicated younger, which possibly reflected secondary heating, while ones of the others indicated consistent with previous thermochronometric data. Integrated with previously obtained ZHe data about 7 samples, the Utaosa rhyolite in the previous study showed a small age dispersion in grain ages, which infers a suitable candidate for the ZHe age standard. As future prospects, we are planning to conduct geochemical analyses and structure observations of these zircons for exploring the causal factors in age dispersions.

Formation of monolayer VSe from multilayer VSe films via V- and Se-desorption

Sumida, Kazuki; Kusaka, Shotaro*; Takeda, Yukiharu; Kobayashi, Katsuyoshi*; Hirahara, Toru*

Physical Review B, 106(19), p.195421_1 - 195421_7, 2022/11

https://doi.org/10.1103/PhysRevB.106.195421

Denudation process of crystalline nappes in a continental collision zone constrained by inversion of fission-track data and thermokinematic forward modeling; An Example from Eastern Nepalese Himalaya

Nakajima, Toru; Kawakami, Tetsuo*; Iwano, Hideki*; Danhara, Toru*; Sakai, Harutaka*

Journal of Geophysical Research; Solid Earth, 127(5), p.e2021JB023630_1  - e2021JB023630_33, 2022/05

https://doi.org/10.1029/2021JB023630

The thermochronological methods were applied to the Higher Himalayan Crystalline (HHC) nappe and the underlying Lesser Himalayan sediments (LHS) to elucidate the denudation process of the middle- and upper-crust of eastern Nepal over the geological time scale. The thermochronological inverse analysis was undertaken for new results of fission-track (FT) age and FT length data of zircon and apatite in order to reconstruct the time-temperature () paths in the temperature range of 60-350 degree. Eight paths obtained along the across-strike section showed that the cooling process of the HHC nappe was characterized by following three aspects: (1) gradual cooling followed by rapid cooling and subsequent gradual cooling, (2) northward-younging of the timing of the rapid cooling, (3) gradual cooling followed by ca. 2 Myr rapid cooling in the frontmost part of the HHC nappe. The observed FT ages and paths were then compared with those predicted by forward thermokinematic modeling. The results of the thermokinematic modeling for the Flat-Ramp-Flat MHT model, in which the HHC and the underlying LHS are denudated accompanied with the movement of the Main Himalayan Thrust (MHT), well reproduced the observed paths and FT ages in eastern Nepal. This suggests that the observed FT ages and paths reflect a denudation process driven by the movement of the MHT showing the flat-ramp-flat geometry, and that the denudation rate and its spatial distribution have roughly been constant in eastern Nepal since ca. 9 Ma.

Improvement of nano-polycrystalline diamond anvil cells with Zr-based bulk metallic glass cylinder for higher pressures; Application to Laue-TOF diffractometer

Yamashita, Keishiro*; Komatsu, Kazuki*; Ohara, Takashi; Munakata, Koji*; Irifune, Tetsuo*; Shimmei, Toru*; Sugiyama, Kazumasa*; Kawamata, Toru*; Kagi, Hiroyuki*

High Pressure Research, 42(1), p.121 - 135, 2022/03

https://doi.org/10.1080/08957959.2022.2045982

Short-range magnetic interaction in a monolayer 1-VSe film revealed by element-specific X-ray magnetic circular dichroism

Sumida, Kazuki; Takeda, Yukiharu; Kusaka, Shotaro*; Kobayashi, Katsuyoshi*; Hirahara, Toru*

Physical Review Materials (Internet), 6(1), p.014006_1 - 014006_8, 2022/01

https://doi.org/10.1103/PhysRevMaterials.6.014006

We investigated the intrinsic magnetic properties of the two-dimensional ferromagnetic candidate monolayer 1-VSe films using X-ray magnetic circular dichroism (XMCD), an element-specific magnetic probe. By performing high-resolution measurements, we succeeded in detecting a clear XMCD signal from the atomically thin 1-VSe films under an external magnetic field. Through manipulation of the X-ray incidence angle, we were able to disentangle the in-plane and out-of-plane magnetic properties and found a strong magnetic anisotropy. Moreover, magnetic field- and temperature-dependent XMCD revealed that there is no long-range ferromagnetic ordering even at 6 K, but short-range ferromagnetic and antiferromagnetic interactions between neighboring vanadium ions exist. Such low-temperature magnetic behavior signifies that the monolayer 1-VSe is on the verge of ferromagnetism, and this fact accounts for the reported ferromagnetism in VSe-based heterostructures.