著者

正井 泰夫 吉野 正敏 谷内 達 中村 和郎 米倉 伸之 戸所 隆 小池 一之 斉藤 功

出版者

公益社団法人 日本地理学会

雑誌

地理学評論 Ser. A (ISSN:00167444)

巻号頁・発行日

vol.73, no.4, pp.288-304, 2000-04-01 (Released:2008-12-25)

著者

鈴木 康弘 池田 安隆 渡辺 満久 須貝 俊彦 米倉 伸之

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.42, no.2, pp.151-159, 1989-06-24 (Released:2010-03-11)

参考文献数

17

被引用文献数

5 2

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Many active faults trending N-S along basin-mountain boundaries are recognized in Northeast Japan, but only a few of them have experienced surface faulting in historical time; most of them seem to have been quiescent in the past several hundred years or more. Thus earthquakes are anticipated to occur from these active faults in the near future. To detect the recurrence intervals of faulting, which can be obtained by the excavation study, is indispensable for the long term prediction of earthquakes.We excavated a trench at Kitasakai, Sakata City, across the Kannonji fault, one of the eastern boundary faults of the Shonai plain, Northeast Japan, in order to reveal its late Holocene activity including a possible faulting event associated with the Shonai earthquake (M=7.0) of 1894 A. D., which caused severe damage along this fault.Our excavation has revealed that (1) the last surface faulting event on the Kannonji fault occurred in a period from 2, 500 years B. P. to 1894 A. D., and that (2) no surface faulting occurred (at least at the trenching site) in association with the Shonai earthquake of 1894. Careful examination of historical records, however, strongly suggests that the earthquake of 1894 was also generated from this fault; it is likely that thick, unconsolidated sediments prevented the rupture from propagating up-dip to the surface. These results indicate that the interval between the last two earthquakes originating from the Kannonji fault is less than 2, 500 years. It could be 1, 000 years, because the event revealed by excavation is possibly correlated to the historically-documented earthquake of 850 A. D..

著者

吉川 虎雄 太田 陽子 米倉 伸之 岡田 篤正 磯 望

出版者

公益社団法人 日本地理学会

雑誌

地理学評論 (ISSN:00167444)

巻号頁・発行日

vol.53, no.4, pp.238-262, 1980

被引用文献数

44

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ケルマデック諸島南端部に近いニュージーランド北島プレンティ湾南東岸地域の海成段丘は,上位からマタカオア・オタマロア・テパパ・テアラロアの4段丘に分類される.これらの各段丘は,いずれも海進を示す地形と堆積物とを伴い, 4回の高海面期の存在を示す.段丘をおおうテフラの細分とそれらのフィッション=トラック年代,段丘堆積物の14C年代から,段丘の形成期は,上位のものからそれぞれ約22~23万年前,約12~13万年前,約8~10万年前,約4,000~5,000年前と推定される.<br> 各段丘面の高度分布から,この地域では, (1) 南東から北西への傾動と, (2) 北縁部における北への著しい擁曲とが認められる. (1) は,明瞭な二つのヒンジによって, (1a) 南東部の急な傾動, (1b) 中央部のゆるやかな傾動,および (1c) 北西部の沈降とに分かれる. (1b), (1c) および (2) は,この地域の山地の成長を示すが, (1a)は山地地形とは調和しない.段丘面は古いものほど同じ様式でより著しく変位しているので,第四紀後期には各地域ごとに同じ様式の地殻変動が継続したことを示す. (1a)の隆起や傾動の規模および速さは,ニュージーランドでは最大級の値であり,環太平洋地域の他の島弧一海溝系におけるそれらに匹敵する.このことと,この地域の海溝に対する位置関係から, (1a)はケルマデック海溝内縁に発生する大地震に伴う地殻変動によるものと考えられる.

著者

米倉 伸之 辻 誠一郎 岡村 道雄

出版者

日本第四紀学会

雑誌

第四紀研究 (ISSN:04182642)

巻号頁・発行日

vol.36, no.5, pp.283-286, 1997-12-01

参考文献数

4

被引用文献数

1

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The aims of the symposium &ldquo;Termination of Last Glaciation and the Formation and Development of Jomon culture in Japan&rdquo; are to clarify (1) what changes have occurred in natural environments in and around the Japanese Islands from the Last Glacial Maximum to the Postglacial periods, (2) what changes have occurred from Late Paleolithic culture to Jomon culture in terms of the relationship between natural and cultural environments, in paticular changes in coastal and land ecosystems and ways of human life, and (3) how and when the Jomon culture was established in terms of natural environmental changes.<br>The symposium consisted of three different parts: (1) Last Glacial Maximum (the age of upper Paleolithic culture, 20-15ka), (2) a transition period from Late Glacial to Postglacial (the age of formation of Jomon culture, 15-10ka), and (3) Postglacial period (the age of the development of Jomon culture, after 10ka). The topics were presented by three speakers for each part from the viewpoints of geology, paleoecology, pedology, and archeology.<br>The topics of presentations in the symposium are the following: Upper Paleolithic culture in Japan and East Asia (Masao Ambiru); Spatial distribution of the vegetation around the Last Glacial Maximum in Japan (Mutsuhiko Minaki); Paleoenvironmental changes of the Japan Sea since the Last Glacial period (Ryuji Tada); A land ecosystem in the transition to the Jomon age (Sei-ichiro Tsuji); The formation of Jomon culture in the Southern and Northern parts of Japanese Islands (Michio Okamura); Soil formation and the environmental change (Kan-ichi Sakagami); Development of Jomon villages (Yasuhiro Okada); Forest vegetation and utilization of wood during the Jomon period in Japan (Mitsuo Suzuki and Shuichi Noshiro), and Jomon agriculture: retrieval of evidence (Masakazu Yoshizaki). The discussions in the symposium have focused on the relationship between the changes in natural environments and ways of human life, in particular the change of land ecosystems and the utilization of natural resources.<br>The state of the art in studies of the natural environmental changes from the termination of the Last Glacial to the Postglacial and their relations to the regional development from the upper paleolithic culture to the Jomon culture in Japan are reviewed from various viewpoints, and future tasks of research are presented.

著者

米倉 伸之

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.77, no.1, pp.1-23, 1968-02-25 (Released:2009-11-12)

参考文献数

34

被引用文献数

14 11

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The Kii peninsula, located on the Pacific coast of central Honshu, is fringed with coastal terraces in its southern part, while its east and west coast are characterized by ria shorelines. The purposes of this paper are to clarify coastal development of the peninsula, especially the history of vertical changes in sea level in its coastal region, and secondly, to examine the relation between the mode of Quaternary crustal movement (especially its vertical component) and recent crustal movement associated with contemporary seismic activity.Coastal terraces and an interpretation of their developmentCoastal terraces, developing along the southern coast of the Kii peninsula (Fig. 2), are mostly rocky abraded terraces covered with thin marine beds. In the northern part of the east coast (north of Shingu) and at the mouths of some rivers, however, some marine terraces are composed of marine sediments overlying fluvial beds. The coastal terraces are classified into two levels of the high and low terraces in the surroundings of Shingu, where they are typically developing (Fig. 4). Both levels of the terraces are further subdivided into some sublevels which are dentoted by H1, H2, H3 and H4 in the high terraces and L1, L2 and L3 in the low terraces respectively in the descending order. The height of each sublevels at Shingu are 125, 113, 95, 61, 49 and 39 meters above sea level. The highest terraces H1 are dissected into narrow hill ridges, overlaid by round gravel beds more than 20 meters thick. The H2, H3 and H4 terraces are rocky abraded ones. The most extensively developing terraces Li are composed of marine sediments underlaid by fluvial beds more than 40 meters in thickness. The L2 and L3 terraces are marine or fluvial terraces which have been formed cutting down the L1 terraces. Alluvial plains (denoted by A) do not so extensively develop along the coast, except at the mouths of the rivers. Judging from some boring data, alluvial formations at the mouths of the rivers are more than 30 meters thick (Fig. 3). From these facts it is concluded that the Hi and Li terraces and alluvial plains are depositional surfaces composed of thick marine and fluvial deposits, which are filling submerged fluvial valleys and, therefore, that the coastal region, being interrupted by temporary submergence, has been emerged in precess of the formation of the coastal terraces. The other terraces H2, H3, H4, L2 and L3 have no feature indicating submergence and, therefore, are considered to have been formed in process of emergence. Judging from the thickness of deposits, amplitude of submergence during the later two periods is considered to be greater than that during the previous period.As to the process of formation of alluvial plains, rapid submergence of this period is regarded in another regions as being largely due to eustatic rise in sea level caused by world deglaciation from the results of the researches on submerged topography, marine topography, succession of alluvial formations, absolute age determination of alluvial marine beds, climatic changes and etc. The process of formation of alluvial plains in the Kii peninsula is inferred to be the same as in another regions from the submerged fluvial valleys and the thickness of alluvial formation and, therefore, the submergence during the last period was caused by eustatic rise in sea level.

著者

米倉 伸之

出版者

東京大学理学部

雑誌

東京大学理学部弘報

巻号頁・発行日

vol.21, no.4, pp.14-15, 1990-03