著者
吾妻 崇 太田 陽子 小林 真弓 金 幸隆
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.69, no.5, pp.365-379, 1996-05
参考文献数
12
被引用文献数
1

The Nojima earthquake fault appeared along the recognized active fault in the northwestern part of Awaji Island in association with the 1995 Hyogoken-Nanbu Earthquake. This earthquake fault is dominated by right-lateral offset (max. 1.7m), with a high-angle reverse fault which has a maximum verlical displacement of 1.3m uplift on the southeastern side. We have repeated the measurement of seven profiles of the fault scarp at two areas (Hirabayashi, Ogura). The fault scarp of the Hirabayashi area (profiles 1-4) is composed of the Plio-Pleistocene Osaka Group at the base and is overlain by an unconsolidated gravel bed at the top. The Ogura area (profiles 5-7) is entirely underlain by the Plio-Pleistocene Osaka Group. The fault scarp in these two areas is characterized by an overhanging slope due to thrusting of the upthrown side. Scarp retreat at Hirabayashi occurred in association with the sudden collapse of the gravel bed and proceeded more quickly than at Ogura, where fault scarp retreat proceeded by exfoliation of the fault plane as well as partial collapse of the Osaka Group. These facts strongly indicate that the lithological control is most significant for the formation of original fault scarp as well as retreat. The retreat of fault scarp was very slow after March to June at Hirabayashi and June to July at Ogura, and proceeded more quickly than some of seismically generated normal faults.
著者
大村 明雄 太田 陽子
出版者
Japan Association for Quaternary Research
雑誌
第四紀研究 (ISSN:04182642)
巻号頁・発行日
vol.31, no.5, pp.313-327, 1992-12-30 (Released:2009-08-21)
参考文献数
34
被引用文献数
8 4

琉球列島の喜界島・波照間島・与那国島および大東諸島の南・北両大東島に発達する更新世サンゴ礁段丘の地形層序と段丘構成物の生相および岩相解析, さらにサンゴ化石のウラン系列 (α-spectrometric 230Th/234U) 年代測定結果を総括した. それによって, 各島々で後期更新世における高海水準期 (酸素同位体ステージ7, ステージ5およびステージ3) の汀線を認定し, それらの現在の高度と Chappell and Shackleton (1986) による古海面変化との比較から, 例えば島の誕生時期・その後の隆起量および速度・傾動の方向などを含めた地殻変動史の点で, 5島それぞれが極めて個性的なことが明確になった.
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

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
太田 陽子 ピラツオリ P. 河名 俊男 森脇 広
出版者
The Association of Japanese Geographers
雑誌
Geographical review of Japan, Series B (ISSN:02896001)
巻号頁・発行日
vol.58, no.2, pp.185-194, 1985-12-01 (Released:2008-12-25)
参考文献数
25
被引用文献数
7 11

琉球列島南部の小浜島・黒島・波照間島の3島(第1図)について,海成段丘,離水ノッチ,ビーチロック,貝・フジツボ・サンゴ化石など,完新世に形成されたと思われる海岸地形・堆積物・化石を調査した.調査した島の地形分類図,試料採取地点などは第2, 4, 5図に,試料のC-14年代は第2表に示される.これらの3島では約4,000yBPから1,000yBPの間の海水準は今よりわずかに高い位置にあったと思われる.すなわち,小浜島では海成段丘堆積物中の貝や原地性のサンゴのC-14年代はそれぞれ約2,600yBP, 3,300yBPで,旧海面は海抜約1mの位置にある.黒島ではビーチロック中の貝化石のC-14年代は約4,200yBPで,旧海面の年代を示すビーチロックやフジツボがやはり海抜約1mの高さに見出される.以上のように,これらの3島においては約4,000年前以降に今より約1m高い位置に海面があり,それ以降わずかながら離水したことが認められる.しかし,日本の各地にみられる縄文海進最盛期(約6,000年前)を示す資料はこれら3島から現在のところ見出すことはできなかった.なお波照間島の南東岸,高那崎付近の海抜約20mに達する平坦面上にサンゴ石灰岩の巨礫が多数みられる.これはその配列の方向やC-14年代から,1771年の明和地震による津波の堆積物であることが明らかになった.
著者
澤 祥 太田 陽子 渡辺 満久 鈴木 康弘
出版者
Japan Association for Quaternary Research
雑誌
第四紀研究 (ISSN:04182642)
巻号頁・発行日
vol.39, no.3, pp.233-240, 2000-06-01 (Released:2009-08-21)
参考文献数
20
被引用文献数
3 1

庄内平野東縁南部松山町の活断層は,活断層研究会(1991)により確実度IIIとされていたが,更新世後期から完新世に活動を続けた長さ約7kmの活断層であることが明らかになった.これを松山断層とよぶ.松山断層は,撓曲変形と断層背後での逆傾斜を変位地形の特徴とし,東上がりの逆断層と考えられる.松山断層の鉛直平均変位速度は0.2~0.7m/kyrsである.松山断層は酒田衝上断層群の位置とほぼ一致し,酒田衝上断層群の第四紀後期の活動の現れと解釈される.
著者
藤森 孝俊 蒔苗 耕司 山口 勝 川口 隆 太田 陽子
出版者
Tokyo Geographical Society
雑誌
地学雑誌 (ISSN:0022135X)
巻号頁・発行日
vol.99, no.2, pp.166-181, 1990-04-25 (Released:2009-11-12)
参考文献数
18
被引用文献数
1

The 1872 Hamada earthquake (M=7.1±0.2) is one of the major historical earthquakes which accompanied a coseismic uplift and subsidence in the coastal area. This paper intends to examine an implication of the Hamada earthquake for geomorphological development of the Hamada area, based on the investigation of marine terraces, emerged sea level indicators such as sea caves, benches, fossil beds and beach deposits, and fault topography.Two steps of Pleistocene marine terraces are found in the coastal area. Terrace I, c. 40-60 m high, is underlain by weathered beach gravel covered by dune sand which is interbedded by at least four horizons of paleosol. It is considered, that a major interglacial period resulting in strong weathering of Terrace I deposits occurred after the formation of this terrace. Thus, Terrace I can be correlated to the penultimate interglacial, and Terrace II, c. 15-25 m high, underlain by rather fresh gravel bed, to the last interglacial. Accepting this correlation, the uplift rate of the study area must be small, c. 0.1-0.2 m/ka, and is no significant difference in the uplift rate over the study area. Height of emerged sea level indicators associated with the Hamada earthquake is 0.9-1.7 m above the present mean sea level. At least one sea level indicator higher than the emerged sea level at the time of the 1872 Hamada earthquake was found at several locations through the study area including the coast where coseismic subsidence occurred in 1872. Northeast-southwest trending lineaments predominate in the study area and a fault exposure is observed on one of the lineaments suggesting that they are fault origin. Areas of coseismic uplift and subsidence can be seens by turns along these faults.Characteristics of the 1872 Hamada earthquake are summarised as follows, based on the above mentioned geomorphological observation : 1) Coseismic deformation as associated with the Hamada earthquake has not accumulated through the late Quaternary, and this earthquake must be a very rare event with coastal deformation during the Holocene. 2) Distribution pattern of coseismic deformation, that is, the occurrence of small blocks with coseismic uplift and subsidence by turns can be interpreted as an effect of strike-slip movement on the faults.
著者
太田 陽子 小田切 聡子 佐々木 寿 向山 栄
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.58, no.4, pp.385-399, 2006-03-31 (Released:2010-03-11)
参考文献数
19

A flight of late Holocene marine terrace fringes the central area of Puget Sound, and records uplift over an extensive area above the Seattle fault zone. The E-W trending blind thrust fault zone is a source of major seismic hazards in the Seattle metropolitan area. Gravity and seismic reflection surveys indicate a south- dipping fault plane, but its exact location and timing of past activities were unknown. LiDAR topographic mapping of the Puget lowland revealed several fault scarps on the glacial landscape hidden under the dense forest. We observed the fault, offset on the Holocene marine terrace surface and measured the former shoreline height at 97 locations using LiDAR DEM to map terrace deformation patterns and their relation to the faults. Studied areas include 1) Alki Point, 2) the southern part of Bainbridge Island, and 3) the southeastern Kitsap Peninsula near Port Orchard and southwestern Bainbridge Island. The height of the former shorelines marked by the Holocene terrace changes from ca. 10.7 to 7.3m a. s. l in the west to 12.2 to 10.1m in the east of the Toe Jam Hill fault, and 10.6 to 7.8m in the west to 9.7 to 7.9m in the east of the Waterman Point fault. These changes indicate differential uplift of the terrace surfaces across the faults. There are two newly identified faults in this study. One is the Point Glover fault that is marked by a scarp in the LiDAR map and associated 2m offset of the terrace surface. The other is the South Beach Point fault inferred by the northward tilt of the terrace surface. Because these faults strike E-W, parallel to the main Seattle Fault on its south side, and have south-facing scarps and north-dipping fault planes, they are probably back-thrsuts to the main Seattle Fault. The width of the backthrust zone is at least 4km. The age of the terraces approximately coincides with the most recent faulting event on the surface fault (at least for Toe Jam Hill Fault, ca. 1000yr BP), thus the differential uplift probably occurred simultaneously with fault movement. Although the surface backthrust scarps are less than a few kilometers long and vertical offset is 2-3m, the total amount of uplift reaches about 12m. Subtracting the effect of the vertical displacement and the amount of northward tilting, the uplift of several meters still remains on the Seattle fault zone of over about 4km wide. This broad zone of uplift is not due to the slip on the subsidiary backthrusts, but probably due to the blind thrust of the main Seattle fault. We infer that at least some of the coastal deformation is caused by broad surface upwarping above the Seattle fault and that the upwarping occurred at ca. 1000yrs BP, associated with ruptures on at least three of the backthrusts. The uplift and faulting may represent the largest earthquake in the Puget Sound area during the late Holocene.
著者
太田 陽子
出版者
Japanese Society for Active Fault Studies
雑誌
活断層研究 (ISSN:09181024)
巻号頁・発行日
vol.2010, no.32, pp.57-72, 2010

This paper summarises the results on active fault studies obtained mainly by the author's work during the last 10 years. The 1999 Chichi earthquake makes a turning point for active faults study. Many international and interdisciplinary works have been carried out for active faults studies, in which the author has participated in the field of geomorphological study of active fault. Her main contribution is a discussion on the close relationship between the 1999 surface trace and preexisting active fault, estimation of tilt rate and relation between the main fault and subsidiary fault, the possible segmentation based on trenching data (Chelungpu Fault), finding some new active faults and discussion of their implication for the geomorphic evolution, as well as seismotectonic significance (Tunglo Fault System and Touhuanping Fault, northwest Taiwan). Ongoing works on the reverse faults in southwestern Taiwan, are briefly summarized, including significant effect of rapid denudation, that may cause underestimation of length of active faults.
著者
兼子 伸吾 太田 陽子 白川 勝信 井上 雅仁 堤 道生 渡邊 園子 佐久間 智子 高橋 佳孝
出版者
日本生態学会
雑誌
保全生態学研究 = Japanese journal of conservation ecology (ISSN:13424327)
巻号頁・発行日
vol.14, no.1, pp.119-123, 2009-05-30
参考文献数
34
被引用文献数
1

The aim of this study was to evaluate the comparative importance of habitat types for the conservation of biodiversity. We determined the number of endangered vascular plant species for each habitat type using the regional Red Data Book that contains information for five prefectures in the Chugoku region, western Japan, together with data on the area covered by each habitat type obtained from the fifth national vegetation survey. The habitat types were classified as "forest", "agricultural field," "wetland," "rocky ground," "grassland," or "seaside." Although many of the listed endangered species belonged to forest habitats, at the regional level, the species/area ratios were higher in the grassland, wetland, and seaside habitats than in the forest and agricultural field habitats. However, the conservation priorities for the endangered plant species in relation to habitat type showed only a slight variation among the prefectures examined.
著者
太田 陽子 松田 時彦 平川 一臣
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.15, no.3, pp.109-128, 1976-10-30 (Released:2009-08-21)
参考文献数
28
被引用文献数
14 9

The Noto Peninsula, which projects northeastwards from central Japan is the largest peninsula in the area along the Sea of Japan. This peninsula mostly consists of low relief erosion surfaces and marine terraces truncating the Neogene rocks. Many active faults which displace these geomorphic surfaces as well as alluvial fans are observed as shown in Fig. 1. Figures 2 to 12 represent the detailed topographies and profiles near and across the active faults. All the active faults are expressed as clear fault scarps or scarplets, and most of them are reverse faults with upwarping of the terrace surfaces on the upthrown side.Active faults in this peninsula are classified into three types according to their bearing on geomorphic development. Type I is the first order active fault which resulted in the differentiation of mountain blocks as indicated in Fig. 1. Bijosan I, II and Sekidosan Faults belong to this type. Ochi Depression delineated by these faults at both margins is a kind of ramp valley in a restricted sense rather than graben, as shown in Fig. 13. Fault scarplets at younger uplifted fans (L1) indicate the faulting has still continued until recently. Type II is the second order fault, represented by large scale height difference of marine terraces, and caused subdivision of each mountain block. Togigawa and Sakami Faults belong to this type. All the other active faults except those mentioned above belong to type III, which has resulted in local deformation of marine terrace surfaces. Faults of this type are usually less than 2km in length and less than 20m in vertical displacement. It is especially interesting that the seaward portion of terrace surfaces generally upthrust against their inland parts. Therefore, active faults of type III can be easily recognized by such an abnormal inland-facing scarplet on terrace surface.Active faults in this area are listed in Table 3. It is noticed that the rate of faulting is always more than 10cm/1, 000 years in types I and II, while it is usually less than that in type III. The amount of vertical displacement even in type III is, however, thought too large to be caused by a single earthquake, so that repeated faultings must be considered.Direction of principal axis of maximum compressive stress is N40-60°W, which is inferred from the frequency distribution of trend of active reverse faults shown in Fig. 14. Fault mechanism of a destructive earthquake of 1933 shows also a maximum pressure direction of approximately E-W, probably with a reverse faulting. The direction above mentioned is almost the same as that in the inland areas of central Japan. It is noteworthy, however, that there is a clear difference in fault type between the Noto Peninsula and the other areas of central Japan where strike-slip active faults predominate.
著者
石橋 克彦 太田 陽子 松田 時彦
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.35, no.2, pp.195-212, 1982-06-25 (Released:2010-03-11)
参考文献数
19
被引用文献数
1 1

Uplifted Holocene marine terraces of Hatsu-shima Island (0.44km2) in the western part of Sagami Bay on the Pacific coast of central Japan have been investigated with special reference to the late Quaternary seismic crustal movement of the island. Hatsu-shima Island, which is located at the top of the western steep scarp of the northernmost part of the Sagami trough, was uplifted almost uniformly by around 2m at the time of the 1923 Kanto earthquake (Ms=8.2).The whole surface of the island consists of a flight of marine terraces developed on Pliocene volcanics. These terraces are clearly classified into three groups; I, II, and III. Terrace I, the highest (about 50m asl), is distributed only in the southeastern small part of the island. Terrace II, 25-40m asl, is the widest in the island and tilting, generally, northwestward. Terraces I and II have been correlated to Obaradai Terrace of about 80, 000yrs B. P. in age and to Misaki Terrace of about 60, 000yrs B. P. in age, respectively, by SUGIHARA (1980) based on marker tephras covering the terraces.Terraces III, rather narrow but well defined especially in the northern and western parts of the island, is distributed along the present shoreline at the foot of a former sea cliff as high as about 20m surrounding Terrace II (or I in the southeastern part). In this paper they are subdivided into three; IIIa, IIIb, and IIIc. Terrace IIIa, the highest and widest among group III, is rather flat with about 10m asl inner margin. Planned excavation at three localities on this terrace has revealed that terrace deposits composed of marine gravel and sand of 1.5-2m thickness rest unconformably on rather weathered bed rock. Fossil shells that were obtained at the base of terrace deposits at Excavation B, which are judged to be in situ and to represent the terrace's age, have been dated at 6, 730±190 14C yrs B. P. (GaK-9080). From this 14C date, as well as from the topographical features, Terrace IIIa can be interpreted as the highest Holocene terrace formed about 6, 000 years ago (so-called Numa Terrace). The height of former shoreline is estimated at around 9m asl. Terraces IIIb and IIIc are narrow emergent shingle beach, whose inner margins are 6-7m asl and about 4m asl, respectively. IIIc includes the emergent beach of 1923 in its lowest part. Although the topographical separation between IIIb and IIIc is not necessarily clear, they can be distinguished from each other as IIIb surface is covered by dense vegetation including many pine trees which have been growing since before the 1923 coseismic uplift, whereas IIIc surface has no vegetation. Therefore, it is almost certain that at least two times of intermittent emergence had occurred between the formation of Terrace IIIa and the 1923 coseismic uplift. However, the dates of emergence have remained undefined, because 14C dates of fossil shells which were collected from Terraces IIIb and IIIc are so much scattered implying that the materials are not in situ. In the northern part of the island there is a prominent flat surface higher than Terrace IIIa, 10-15m asl, where Hatsu-shima village is situated. In this paper it is named IIIa' Surface and considered a secondary surface modified from Terrace IIIa by landslides of a back scarp and artificial alteration based on its sedimentological features, surrounding topographical features, and rather young 14C dates of materials obtained from this surface.
著者
太田 陽子 松田 時彦 長沼 和雄
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.29, no.1, pp.55-70, 1976-03-10 (Released:2010-03-11)
参考文献数
21
被引用文献数
1 1

Seven steps of marine terraces are well developed on the Ogi Peninsula, Sado Island. The seventh (lowest) one is a raised abrasion bench less than 2m high, emerged at the time of the destructive earthquake of 1802, hence it is named the 1802 terrace. The sixth terrace is about 2-4m high, and probably was formed at the time of Holocene transgression. Higher five terraces (Pleistocene terraces V-I) are well preserved over the most part of the peninsula and have the height of 32-40m, 70-55m, 94-118m, 123-137m and more than 165m, respectively.The height of former shorelines represented by shoreline angle of each terrace shows that all the terraces tilt northward. Generally, the higher the terrace, the larger the amount of tilting. However, the tilt of the lowest two terraces (the 1802 and Holocene terraces) is almost the same, ca. 1.5′. This indicates that the 1802 tilting caused by the earthquake was a first event after the formation of the Holocene terrace of ca, 6, 000 years old and the recurrence interval of the events was more than 6, 000 years. A uniform regional difference of 2m in height between these two terraces is probably interpreted as a superposed result of the eustatic lowering of sea level and a regional uplift during last 6, 000 years.It is possible to estimate the average intervals of earthquakes after the terrace formation by comparing the tilting rate of all Pleistocene terraces with that of the 1802's. Thus, the average recurrence intervals are estimated at about 8, 600 years since Terrace III was formed and about 5, 000 years since Terrace IV was formed. These values are consistent with the interval of more than 6, 000 years which is estimated from tilt of the 1802 and the Holocene terraces. It is concluded, therefore, that the earthquake has taken place repeatedly in a similar manner with a recurrence interval of about 5, 000-9, 000 years during at least last 105 years.Uplift and northward tilting of the Ogi Peninsula at the time of the 1802 earthquake (Magnitude 6.6) is significantly larger than those of Awa-shims at the Niigata earthquake of 1964 (M 7.4), though its magnitude was smaller.This fact and the limited areal deformation by the 1802 earthquake imply that the epicenter of this earthquake was located very close to the coast of the Ogi Peninsula, probably within a few kilometers off Shukunegi. A reverse faulting is inferred to have occurred along a northward-dipping fault plane at the 1802 earthquake.
著者
太田 陽子
出版者
聖学院大学
雑誌
若手研究(B)
巻号頁・発行日
2005

本年度は、昨年度に実施した調査結果を分析し、整理してデータ化することと成果をまとめることに主眼をおいた。研究実施計画に挙げた、以下の1〜3の作業を通して、現在、4として総括を試みているところである。1.構文機能の実態調査昨年度に引き続き、シナリオ集や新聞コーパスを中心に、ハズダ・ニチガイナイ・カモシレナイの実例を収集・分析し、各表現の使用文脈と機能を具体的に記述、リスト化した上で、相互比較を試みた。2.教材分析これも昨年度に引き続き、主要教材(初級教科書15種・中〜上級教科書20種・文法書27種)の例文、練習、解説、場面設定を観察し、その傾向をまとめるとともに、文脈的観点(発話者や聞き手の資格、発話意図、場面設定など)の欠如による問題点などを指摘した。3.調査結果の分析昨年度に日本・中国・韓国・ベトナム・マレーシアにおいて実施した「文型使用意識調査」の結果について、それぞれの回答を、学習者の会話作成例、および意見文における運用例としてリスト化した上で、(1)会話場面での運用における問題点、および(2)文章構成上の位置づけの問題点という観点から分析し、現行の日本語教育における指導に欠けている視点を模索した。4.非断定表現の文脈化と教材化を通した文法記述方法の提案上記の1〜3の作業を通して得た結論を基に、現行教材や教育現場の問題点を補い、学習者の運用に不可欠な文脈情報を踏まえた文法の記述方法の提案を、現在試みている。
著者
Batanova Tatiana A. 太田 陽子 鬼頭 克也 松本 安喜 林 良博 高島 康弘
出版者
社団法人日本獣医学会
雑誌
The journal of veterinary medical science (ISSN:09167250)
巻号頁・発行日
vol.68, no.1, pp.87-90, 2006-01-25
被引用文献数
1

マウス免疫グロブリンG1(IgG1)のFc領域をもつキメラ蛋白を作成し, その免疫学的性状を調べた.この分子は抗体分子の持つ性質のうち, マクロファージによる抗体依存性細胞障害の誘導能, lipopolysaccaride刺激された脾臓細胞によるインターロイキン10産生の増強能を保持していた.