| フルテキストURL | esr_032_cover_j.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2026-03-31 |
| 巻 | 32巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2026 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_032_colophon.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2026-03-31 |
| 巻 | 32巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2026 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/ESR/70297 |
|---|---|
| タイトル（別表記） | Large-scale rainfall characteristics at the heavy rainfall event around the western Japan during 5–7 July 2018 |
| フルテキストURL | esr_032_033_044.pdf |
| 著者 | 加藤 内藏進| 松本 健吾| 大谷 和男| |
| 抄録 | Large-scale rainfall characteristics at the heavy rainfall event around the western Japan for 5–7 July 2018 were analyzed with use of the 10-mimute precipitation data at the surface meteorological observation stations of the Japan Meteorological Agency, and so on. In this case, the area with 3 days total precipitation of near or more than 300 mm was distributed widely from northern Kyushu to Shiga and Fukui Prefectures. As in the many heavy rainfall events around Kyushu District in the mature stage of the Baiu season, contribution of the intense rainfall with more than 4 mm/10-minute (24 mm/h) attained about one third of the areal mean total precipitation. However, it is noted that the "not so intense rain" with less than 2 mm/10-minute (12 mm/h) also contributed to about one third of the huge total precipitation in the wide area. In short, this case could be characterized by the mixture of the western Japan type heavy rainfall event and the eastern Japan type one. |
| キーワード | western Japan heavy rainfall in July 2018 10-minute precipitation data east-west difference of the Baiu precipitation |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2026-03-31 |
| 巻 | 32巻 |
| 号 | 1号 |
| 開始ページ | 33 |
| 終了ページ | 44 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2026 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/ESR/70296 |
|---|---|
| タイトル（別表記） | A trial of lesson practice at the university on the variety of heavy rainfall characteristics based on the 10-minute precipitation data toward promoting the meteorological disaster prevention literacy |
| フルテキストURL | esr_032_021_031.pdf |
| 著者 | 加藤 内藏進| |
| 抄録 | In the disaster prevention education on the heavy rainfall around Japan, it is also important to promote the meteorological literacy on the seasonal and regional differences of their rainfall characteristics such as the convective rain or stratiform rain, together with their total amount of precipitation and their occurrence frequency. As the first step toward the above purpose, the present study made a lesson practice for the university students by utilizing the 10-minute precipitation data for the four heavy rainfall events, in which the types of the heavy rainfall (although all the cases examined in the lesson are relating to the deep convective clouds) are rather different from each other, such as the differences of the rainfall intensity at the peak time, short-period variation of the rainfall intensity and the persistency of the rainfall including the "not so intense rainfall". The reports by the students seem to perceive the different features among these events briefly, but the students' attention to how long the intense rainfall with short-period variation or "not so intense rainfall" lasted was not so sufficient. |
| キーワード | disaster prevention education variety of the heavy rainfall characteristics meteorological disaster prevention literacy use of the 10-minute precipitation data |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2026-03-31 |
| 巻 | 32巻 |
| 号 | 1号 |
| 開始ページ | 21 |
| 終了ページ | 31 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2026 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/ESR/70295 |
|---|---|
| タイトル（別表記） | Petrological study of Sue ware from the Sabukaze kiln site, Okayama Prefecture |
| フルテキストURL | esr_032_009_019.pdf |
| 著者 | 阿南 太士| 野坂 俊夫| 木村 理| |
| 抄録 | The Sabukaze kiln site, a representative ancient tunnel-kiln site in the Kibi region, worked during the Asuka period (from early 7th century to early 8th century) to produce Sue ware including jars, cups, coffins, and ornamental tiles. To determine the provenance of the materials used for the Sue ware, we carried out petrological analyses of 13 Sue sherds, including optical microscopy, X-ray diffractometry, X-ray fluorescence spectroscopy, Raman spectroscopy, and electron-probe analysis. In spite of the difference of production time, all the Sue sherds show close similarities in modal proportion of mineral inclusions with dominant quartz and feldspar, and minor volcanic glass, in chemical compositions of feldspar and interstitial matrix, and in whole-sherd chemical composition. These similarities suggest that the paste materials of the Sabukaze Sue ware were commonly derived from weathered rhyolitic rocks and obtained from the same or neighboring mining site(s) located near the kiln site. |
| キーワード | Sabukaze kiln site Sue ware provenance petrology |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2026-03-31 |
| 巻 | 32巻 |
| 号 | 1号 |
| 開始ページ | 9 |
| 終了ページ | 19 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2026 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/ESR/70294 |
|---|---|
| タイトル（別表記） | Microtremor exploration in Kojima Bay area, Okayama Plain |
| フルテキストURL | esr_032_001_007.pdf |
| 著者 | 山田 伸之| 竹中 博士| |
| 抄録 | This report describes microtremor array observations conducted at two sites for deep exploration and three sites for shallow exploration around Kojima Bay area in the southern Okayama Plain. Based on these records, the ground velocity structures were estimated. The results yielded solutions indicating the depth of the top of the seismic base layer (equivalent to 3 km/s layer) ranges from 140 to 300 m, while the depth of the top of the engineering basement layer (equivalent to 0.6 km/s layer) is approximately about 13–14 m. The shallow exploration results also suggested the possible presence of an inversion layer. These estimated velocity structure models provided a reasonable explanation for the observed phase velocities. |
| キーワード | Okayama Plain Kojima Bay Microtremor array exploration S-wave velocity structure model |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2026-03-31 |
| 巻 | 32巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 7 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2026 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_032_titlepage.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2026-03-31 |
| 巻 | 32巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | © 2026 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_032_cover.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2026-03-31 |
| 巻 | 32巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | © 2026 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_031_cover_j.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2025-03-31 |
| 巻 | 31巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2025 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_031_colophon.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2025-03-31 |
| 巻 | 31巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2025 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/ESR/68676 |
|---|---|
| タイトル（別表記） | Improved sedimentary layer model including the accretionary prism in the fore-arc region of the Ryukyu arc, Japan |
| フルテキストURL | esr_031_001_015.pdf |
| 著者 | 小松 正直| 浦上 想平| 岡元 太郎| 竹中 博士| |
| 抄録 | We combine the recent seismic reflection profiles to construct a new seismic velocity model of the sedimentary layer incorporating the accretionary prism along the Ryukyu trench. In constructing the new model, we refer to the zoning (ZONE1 to ZONE4) identified by Okamura et al. (2017, Tectonophys.). The construction process consists of the following steps: First, we digitize either unconformities or VP=4 to 5 km/s lines as the seismic basement, whichever is more clearly identifiable. Second, the digitized thickness data of the sedimentary layer from the reflection profiles are geometrically modeled and interpolated to make the three-dimensional structure model. Finally, we supplement the external region of the constructed 3-D sedimentary model using the J-SHIS model provided by the NIED to complete the velocity structure model in the entire Ryukyu arc. The main features of our model are as follows: In ZONE1, off Ishigaki-jima island, the thick sedimentary layer extends about 50 km wide from the Ryukyu trench. In ZONE2, off Miyako-jima island, the thinner layer compared to the other zones is found near the trench, with a thin sedimentary terrace covering the area behind it. In ZONE3, off Okinawa-jima island, the sedimentary layer deepens as it approaches the trench. In ZONE4, off Tokara islands, the deepest layer among all zones is identified. We then conduct 3-D finite-difference simulations of seismic wave propagation using the new and the previous models to confirm the improvement of the new model. In the simulations, the effects of the accretionary prism along the Ryukyu trench on the seismic wave propagation are clearly identified. |
| キーワード | Sedimentary layer model Accretionary prism Ryukyu arc |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2025-03-31 |
| 巻 | 31巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 15 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2025 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_031_titlepage.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2025-03-31 |
| 巻 | 31巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | © 2025 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_031_cover.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2025-03-31 |
| 巻 | 31巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | © 2025 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_030_cover_j.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2024-03-31 |
| 巻 | 30巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2024 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_030_colophon.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2024-03-31 |
| 巻 | 30巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2024 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/ESR/66846 |
|---|---|
| フルテキストURL | esr_030_021_035.pdf |
| 著者 | MAURER, Robert| HARKER, Stuart| SUZUKI, Shigeyuki| WHEELER, Allan| |
| 抄録 | Mantle convection currents are the currently accepted driving force for plate tectonics that have ripped apart the continents and created oceans. Because of these actions, continental collisions and ocean closures have resulted. Our paper challenges the conventional concept and provides an alternate, mathematically justified drive mechanism. The pull-push motions of such convection currents in the upper mantle are here concluded to be too weak to be the driving mechanism. Our proposal for such global scale forces concerns the effect of an offset centre of mass of the Earth that results in rotational wobbling. Kepler’s laws of planetary motion demonstrate the rotational behavior of the Earth to be aligned with the Sun on the outward and inward motions of the elliptical orbit. The unbalanced rotation on a fixed gravitational axis results in circumferential stresses on the outer Earth’s rim that is more than strong enough to pull the continental plates apart. The proposed unbalanced rotational stress force equation is shown to be sufficient to drive the cyclic breakup and reassembly of the continental plates, as well as the generation of new oceanic crust and subduction zones. Mantle convection currents are here demonstrated to have a passive rather than active role in the plate movements. |
| キーワード | Differential circumferential tensile force Rotating Earth Offset centre of mass radius of eccentricity |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2024-03-31 |
| 巻 | 30巻 |
| 号 | 1号 |
| 開始ページ | 21 |
| 終了ページ | 35 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | © 2024 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/ESR/66845 |
|---|---|
| タイトル（別表記） | Microtremor exploration in Tsushima Campus, Okayama University |
| フルテキストURL | esr_030_013_020.pdf |
| 著者 | 山田 伸之| 竹中 博士| |
| 抄録 | In this report, microtremor array observations were conducted in the Tsushima Campus of Okayama University, and the subsurface velocity structure was estimated from the analysis of the records. The results indicate that a five-layer S-wave velocity structure from the surface to the seismic basement equivalent layer with thicknesses of 8, 24, 80 and 180 m and velocities of 150, 450, 1100, 1700 and 3200 m/s, respectively, is reasonable. This model explains to some extent the observed phase velocity and H/V spectral ratios. It is also consistent with the surface borehole results. Furthermore, the areal characteristics of the H/V spectral ratios were also presented, allowing us to estimate the trend of the ground structure in shallow areas. |
| キーワード | Okayama Microtremor array exploration S-wave velocity H/V spectral ratio |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2024-03-31 |
| 巻 | 30巻 |
| 号 | 1号 |
| 開始ページ | 13 |
| 終了ページ | 20 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2024 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/ESR/66844 |
|---|---|
| タイトル（別表記） | Petrological characteristics of the stone chamber of Tobiotsuka Kofun, Okayama Prefecture |
| フルテキストURL | esr_030_001_012.pdf |
| 著者 | 金子 峻大| 野坂 俊夫| 清家 章| |
| 抄録 | Tobiotsuka Kofun, a tumulus built on the Misu Hills in the Kofun period, has a horizontal stone chamber made of huge stone blocks with a width up to 2 meters or more. To specify the source of the stone blocks, we carried out the measurement of magnetic susceptibility, petrographic observation, and chemical analysis of minerals. The stones are amphibole-biotite granite with phenocrystic large grains of K-feldspar. The back-wall stone of the chamber has higher magnetic susceptibility than ceiling and side-wall stones, which probably results from a higher amount of magnetite formed by the alteration of biotite in the back-wall stone. Furthermore, the back-wall stone is different from ceiling stone in that it has lower XMg [Mg/(Mg + Fe) mole ratio], lower Al, Ti, and Na + K contents and higher Si contents of amphibole, higher XMg of biotite, and shows a tendency to have higher Na (albite component) contents at rims of plagioclase crystals and lower Ti contents of zircon. These characteristics of the back-wall stone are similar to those of granite exposed in the Koshinzan area about 2 km northeast of Tobiotsuka Kofun, whereas the ceiling and side-wall stones are similar to granite outcrops in the vicinity of Tobiotsuka Kofun, e.g., in the Midoriyama area. It is concluded that the quarry for the back-wall was located at a different place from that for the ceiling and side-wall stones. |
| キーワード | Tobiotsuka Kofun stone chamber granite |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2024-03-31 |
| 巻 | 30巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 12 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2024 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_030_titlepage.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2024-03-31 |
| 巻 | 30巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | © 2024 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| フルテキストURL | esr_030_cover.pdf |
|---|---|
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2024-03-31 |
| 巻 | 30巻 |
| 号 | 1号 |
| ISSN | 1340-7414 |
| 言語 | 英語 |
| 著作権者 | © 2024 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |