著者
徳山 英一 本座 栄一 木村 政昭 倉本 真一 芦 寿一郎 岡村 行信 荒戸 裕之 伊藤 康人 除 垣 日野 亮太 野原 壮 阿部 寛信 坂井 眞一 向山 建二郎
出版者
海洋調査技術学会
雑誌
海洋調査技術 (ISSN:09152997)
巻号頁・発行日
vol.13, no.1, pp.27-53, 2001-03-31
参考文献数
56
被引用文献数
6

We propose the guideline to identify fault in offshore region mainly based on MCS profiles, combining high resolution bathymetric maps and geological data such as bore hole results. Based on the guideline we distinguished total 776 faults developing around Japan since the latest Miocene and 753 faults out of total numbers of faults are interpreted to have been active by Quaternary. Together with distinguishment of fault we examined the attributes of each faults such as surface and vertical distribution, criteria of offset, age of movement, certainty of a fault and so on. <br>The results of the distinguishment and examination of the fault leads to the conclusion that the ongoing tectonic framework around Japan characterized by 1) oblique Subduction along the Nankai Trough, 2) rifting at the Okinawa Trough, 3) E-W compressionl regeme along the Japan Sea margin, 4) E-W compressionl regeme along southwestern margin of the Okhotsk Sea and off southern Hokkaido, 5) E-W compressionl regeme along the Japan Trench, 6) rifting in the central arc of the Izu-Ogasawara Arc has been established since 3 Ma, at the earliest 6 Ma. <br>We utilized high resolution data set which we enable to access. Tow big problems, however, still remain in terms of reliability of fault recognition. Those are 1) age of fault movement and 2) spatial distribution of fault. To solve the first one, new technique is required in order to obtain core samples which provide critical evidence to determine age of fault movement. As is second problem concerned, new intensive seismic survey is indispensable to make a precise fault distribution map, especially in the boundary area between land and sea.
著者
根来 尚
出版者
富山市科学文化センター
雑誌
とやまと自然
巻号頁・発行日
vol.3, no.4, 1981-01-20
著者
東 清二
出版者
琉球大学
雑誌
琉球大学農学部学術報告 (ISSN:03704246)
巻号頁・発行日
vol.23, pp.125-140, 1976-12-01

イワサキクサゼミMogannia minuta Matsumuraの生活史と, 1963年以来サトウキビ圃場において発生密度が増加した原因について調査した。その結果次のことが判明した。(1)25℃, 30℃における卵期間は, 平均でそれぞれ42日, 32日であった。(2)鉢植えサトウキビで飼育した幼虫の1齢終了日はふ化後33&acd;36日, 2齢は63&acd;66日, 3齢は165&acd;170日, 4齢は300&acd;305日, 5齢は640日以後と推定された。また幼虫期間は個体間差が大きいこともわかった。(3)鉢植えサトウキビ及びススキで幼虫を飼育した結果, サトウキビでは2年で羽化する個体が多く, ススキでは3年で羽化する個体が多かった。(4)サトウキビ圃場の更新により幼虫個体数が約95%も減少することがわかった。(5)サトウキビ圃場の成虫は羽化直後平均541個の卵を有しているが, 死後の卵巣内残存卵数は125個で, 約400卵産下することがわかった。ススキ原の成虫はそれぞれ504個, 204個で約300卵産下する。サトウキビ圃場の成虫は産卵数が多いと推定された。(6)天敵は25種類確認された。農薬散布によりアリ類は19&acd;33%の個体数に減少し, クモ類の個体数は26&acd;55%に減少する。(7)これらのことからイワサキクサゼミがサトウキビ圃場において発生するようになったのは, セミの発育経過日数が個体により差があること, 及び株出栽培の増加によりサトウキビ圃場が耕起されずにセミの1世代期間以上も安定した状態で続いたことによるものと考えられた。一度サトウキビ圃場で発生するようになったセミは, 1世代期間が短縮したこと, 産卵数が増加したこと, 株出サトウキビにおいて産卵数が多いこと, 農薬散布によって天敵が減少し, セミの生存率が高くなったことなどで個体数が増加したと判断された。すなわち品種の変遷や栽培方法の変化によってイワサキクサゼミは重要害虫になったものと判断された。
著者
長田 義仁 太田 文彦
出版者
一般社団法人 表面技術協会
雑誌
金属表面技術 (ISSN:00260614)
巻号頁・発行日
vol.36, no.11, pp.434-441, 1985-11-01 (Released:2009-10-30)
参考文献数
65
被引用文献数
1
著者
Fujimoto Takafumi Fujimoto Suzu Murakami Masaru Yamaha Etsuro Arai Katsutoshi
出版者
北海道大学大学院水産科学研究院
雑誌
北海道大学水産科学研究彙報 (ISSN:24353353)
巻号頁・発行日
vol.70, no.1, pp.103-111, 2020-08-24

Tetraploid strains are important sources of diploid gametes available for further expansion of ploidy manipulation. Although artificial induction of tetraploid strains has been attempted by inhibition of a mitotic cell division of zygotes using hydrostatic pressure or temperature treatments at the early developmental stage, successful examples of viable and fertile tetraploid fish were very rare. Because most resultant tetraploid progeny exhibited extremely high mortality. Natural tetraploid variants are considered another source of diploid gametes. In the present study, we tried to induce new strains of tetraploid, triploid and androgenetic diploid using diploid sperm of a tetraploid ginbuna (Japanese silver crucian carp Carassius auratus langsdorfii), which caught at the Jounuma lake, Gunma Prefecture, Japan. New tetraploids, i.e., neo-tetraploids were induced by fertilizing eggs of a diploid goldfish Carassius auratus auratus with diploid sperm of the tetraploid ginbuna, followed by heatshock (40°C for 45, 60 and 75 s) to inhibit the second polar body release at 5 min after fertilization. Although a small number of neo-tetraploid fish survived, we could not obtain any fertile gametes from them in the present study. Triploids were successfully induced by fertilizing eggs of a diploid goldfish with diploid sperm of the tetraploid ginbuna. Some resultant triploid males produced aneuploid sperm at the age of maturation. Androgenetic diploids were induced by fertilizing UV-irradiated eggs of diploid goldfish with diploid sperm of the tetraploid ginbuna. A mature androgenetic diploid produced fertile haploid sperm.
著者
浅野 竜太 磯田 豊 小林 直人 中村 知裕 伊藤 薫
出版者
北海道大学大学院水産科学研究院
雑誌
北海道大学水産科学研究彙報 (ISSN:24353353)
巻号頁・発行日
vol.70, no.1, pp.63-76, 2020-08-24

A new type of mechanism for the generation of vertical circulation is revealed with the use of numerical experiments for the bended channel model. In the steady passage-flow experiment with a flat bottom and no bottom friction, a remarkable vertical circulation is formed only at the downside of bended corner where a negative horizontal shear flow dominates. Specifically, we call this type circulation “Negative Shear induced Vertical Circulation (NSVC)”, which is caused through the dynamical unbalance of gradient flow and the vorticity balance between the lateral vorticity advection and the sea surface divergence. A field observation was carried out around the Ooma-zaki area in the eastern Tsugaru Strait to confirm an enhanced downward flow expected by the realistic experiment including the bottom slope and friction. The spatial istributions of water temperature support the existence of this downward motion.
著者
堀尾 一樹 磯田 豊 小林 直人 千葉 彩
出版者
北海道大学大学院水産科学研究院
雑誌
北海道大学水産科学研究彙報 (ISSN:24353353)
巻号頁・発行日
vol.70, no.1, pp.41-62, 2020-08-24

If there is the coastal upwelling, it is common to think that the upward advection of cold deep water will make the coastal side cooler than the offshore side. Shelf slope upwelling (SSU) presented in this study, however, occurs only when the shallow coastal side is rather warm due to a continuous sea surface heating in summer. The present study investigated the formation process of such SSU using a numerical model driven by surface heating. From the results of examining unsteady state of heat budget and dynamic balance, SSU was found to be a kind of compensation flow, not the bottom Ekman flow. That is, to satisfy continuity in a vertical section, the offshore flow caused by the horizontal density/temperature gradient was supplemented by the shoreward flow strongly confined to the sloping seabed. This SSU will probably be one of the important flows contributing to material transport, e.g., unused nutrients and anoxic water etc., from deep to near coast in summer, while it is difficult to prove the existence of SSU even indirectly from the observed water temperature.