著者

齋藤 有 田村 亨 増田 富士雄

出版者

Tokyo Geographical Society

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.114, no.5, pp.687-704, 2005-12-25

被引用文献数

3 12

---

Hyperpycnal flow is one type of turbidity current, which is generated at a river mouth when the suspended sediment concentration of river discharge is so high that the density of the effluent exceeds the water of the receiving basin. Generations of this type of flow have become a common phenomenon recently. A lot of hyperpycnal flow deposits are expected to be preserved naturally in stratigraphic records. Hyperpycnal flow deposits (hyperpycnites) might become an innovative factor for turbidite paradigm considering the particularity of the flow, and bring facies analysis towards the next step. In this review paper, the criteria for identifying hyperpycnal flow deposits from strata are proposed by summarizing studies on hyperpycnal flow and its deposits. Typical characteristics of hyperpycnal flow include : (1) vertical succession composed of 2 parts, inversely-graded lower part and normally-graded upper part, (2) internal scour surface, (3) repetitive alternation of fine-grained and coarse-grained layers, or laminated and massive layers, (4) abrupt pinch-out of beds, and (5) inclusion of terrestrial materials such as leaves. Hyperpycnal flow gradually waxes and then wanes to terminate in response to flood conditions, resulting in (1). The internal scour surface (2) developed in accordance with the degree of waxing. Fluctuations of flow velocity and sediment concentration due to changes of river discharge and/or internal waves can occur during the flow event, and lead to repetitive alternation of (3). Because of the fresh interstitial water, the marine hyperpycnal flow might start to lift off after losing suspended sediments to the degree that the density of the flow is exceeded by ambient saline water. This results in (4) at the lifting point. Terrestrial materials referred to in (5) are the result of the fact that the hyperpycnal flow originated from terrestrial floods.<BR>A much wider variety of deposits, which form in one history of a turbidity current, than that expected from the Bouma sequence model, is shown. Exploration of the variety has just started.

著者

渡部 景隆

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.105, no.6, pp.694-702, 1996-12-25 (Released:2010-04-23)

参考文献数

16

被引用文献数

2 1

著者

柳田 誠 藤原 治 後藤 憲央 佐々木 俊法

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.113, no.6, pp.835-847, 2004-12-25 (Released:2009-11-12)

参考文献数

22

被引用文献数

5 4

---

The authors re-examine conventionally used terms for hills on the basis of a morphometric study of landforms in Japan. Relative relief and drainage density are calculated for every 250 m grid on topographic maps.Figure 2 shows relative relief on the vertical axis and drainage density on the horizontal axis. Hills are clearly delineated from mountains by these parameters. The relative relief for hills is smaller than 110 m120 m, and the drainage density is greater than 4050 streams/km2. The Shiranuka Hills in Hokkaido should more appropriately be called the Shiranuka Mountains, because of their high mean relative relief (134.3 m) and lower drainage density.Figure 2 also indicates a possible subdivision of hills into 2 types, or 'flat topped hills' with a relative relief of less than 60 m, and 'ridge hills' with a relative relief of 60 m 120 m. The standard deviation of relief energy can also be taken as a criterion to distinguish the 2 types of hill, namely, the flat topped hills have a standard deviation of 8.120.6, in contrast to the ridge hills, which have a standard deviation of 21.029.8.The drainage density generally increases corresponding to the length of time through which terraces are transformed into hills and the amount of uplift. Therefore, hills have greater drainage density than terraces. But, it is worthy of note that the drainage density is never greater than 7080 streams/km2. The greatest density is found in the Oku-Noto Hills, one of the ridge hills 480, 000780, 000 years old. Indications are that the development of a drainage system culminates at some stage between flat-topped hills and ridge hills, and then valleys are gradually unified, resulting in a lower drainage density.Both flat-topped hills and ridge hills may be derived from various origins such as terraces, depositional surfaces of pyroclastic flows, dissected Tertiary or early Quaternary soft rocks, or degradation of mountains with medium relief. But, the formation of ridge hills requires a greater speed of uplift, and rocks that are hard enough to sustain steep slopes with a relative relief of 80 m120 m. The conditions being the same, ridge hills are older than flat-topped hills.

著者

小林 貞一

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.87, no.5, pp.274-275, 1978-10-25 (Released:2009-11-12)

著者

小林 貞一

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.95, no.2, pp.143-144, 1986-04-25 (Released:2009-11-12)

著者

田近 英一

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.116, no.1, pp.79-94, 2007-02-25 (Released:2009-11-12)

参考文献数

86

被引用文献数

1

---

Liquid water on the surface of the Earth might have frozen entirely at least 3 times during the history of the Earth (650 Ma, 700 Ma, and 2.2 Ga). Assuming such extreme conditions, the snowball Earth hypothesis explains several unusual geological features associated with glacial deposits in the Proterozoic glaciations. Life should, however, have faced serious crises during these glaciations because liquid water is necessary for life. In particular, survival of photosynthetic algae, which are supposed to have appeared before the Neoproterozoic glaciations, might have been difficult if the surface water froze completely. There would have been refugia for life during the global glaciations. Life could have survived if the equatorial ocean was not completely frozen (soft-snowball condition), or equatorial sea ice might have been very thin (on the order of 10 meters). Even if these conditions were not achieved, life could have survived in shallow hot springs around volcanic islands. It would be much more difficult for eumetazoa to survive such severe conditions if they appeared before the Neoproterozoic glaciations as suggested by molecular clock studies. The appearance of eumetazoa after the last global glaciation (Marinoan glaciation), as suggested by the paleontological record, however, avoids this problem.

著者

柴山 元彦

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.105, no.6, pp.718-722, 1996-12-25 (Released:2009-11-12)

被引用文献数

2 2

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.21, no.3, pp.206-206, 1909

被引用文献数

1

著者

速水 格

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.83, no.3, pp.157-171, 1974-06-25 (Released:2009-11-12)

参考文献数

37

---

The phylogeny and mode of evolution of a Liassic oyster Gryphaea have been studied by many European and American outstanding evolutionists since TRUEMAN's (1922) classical interpretation of its morphological change. For these fifty years many useful ideas and methods in the study of morphogenesis, biometry, autoecology and functional morphology were introduced into paleontology through this material. In this report some of these works are reviewed and evaluated, and what is suggested to general evolutionary paleontology is considered.

著者

増田 富士雄 藤原 治 酒井 哲弥 荒谷 忠

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.110, no.5, pp.650-664, 2001-10-25 (Released:2009-11-12)

参考文献数

48

被引用文献数

14 17

---

Relative sea-level changes and variations in shoreline progradation rate over the past 6000 years are elucidated from the elevations of the beach deposits, their 14C ages, and the geographic position of each locality on the Kujukuri strand plain, Pacific coast of the Boso Peninsula, central Japan. These past sea-levels were +4 to +6 m above the modern sea-level (high-stand stage) at 6000 to 5300 calendar years B.P., +3 to + 4.5 m (stable stage) at 5000 to 3500 years B.P., declined from +1.2-+ 3.4 m to + 0.5-+ 2.1 m (falling stage) at 3300 to 2250 years B.P., and were-1.5--1 m to + 1 m (stable stage) from 1650 to 250 years B.P. ; sea level is 0 m at present. The detailed changes revealed by this new method strongly imply the existence of several rapid uplifts (0.4 to 1.2 m per event) at 5100 to 5500 years B.P., 3400 years B.P., 2400 years B.P., 1650 years B.P., and 0-250 years B.P. The uplifts were co-seismic, because the speed of occurrence seems to have been high, and the events are generally associated with so-called “tsunami deposits.” Co-seismic uplift in this region has not been reported previously from historical records or geological evidence.

著者

矢野 桂司 中谷 友樹 磯田 弦 高瀬 裕 河角 龍典 松岡 恵悟 瀬戸 寿一 河原 大 塚本 章宏 井上 学 桐村 喬

出版者

Tokyo Geographical Society

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.117, no.2, pp.464-478, 2008-04-25

被引用文献数

2 19

---

バーチャル京都は,歴史都市京都の過去,現在,未来を探求することを目的に,コンピュータ上に構築されたバーチャル時・空間である。本研究では,最先端のGISとVR技術を用いて,複数の時間スライスの3次元GISからなる4次元GISとしてのバーチャル京都を構築する。本研究は,まず,現在の京都の都市景観を構築し,過去にさかのぼる形で,昭和期,明治・大正期,江戸期,そして,京都に都ができた平安期までの都市景観を復原する。<br> バーチャル京都を構築するためには以下のようなプロジェクトが行われた。a)京都にかかわる,現在のデジタル地図,旧版地形図,地籍図,空中写真,絵図,景観写真,絵画,考古学資料,歴史資料など位置参照可能な史・資料のGIS データの作成,b)京町家,近代建築,文化遺産を含む社寺など,現存するすべての建築物のデータベースおよびGISデータの作成,c)上記建築物の3次元VRモデルの構築,d)上記GISデータを用いた対象期間を通しての土地利用や都市景観の復原やシミュレーション。<br> バーチャル京都は,京都に関連する様々なデジタル・アーカイブされたデータを配置したり,京都の繊細で洗練された文化・芸術を世界に発信したりするためのインフラストラクチャーである。そして,Webでのバーチャル京都は,歴史的な景観をもつ京都の地理学的文脈の中で,文化・芸術の歴史的データを探求するためのインターフェイスを提供する。さらに,バーチャル京都は,京都の景観計画を支援し,インターネットを介して世界に向けての京都の豊富な情報を配信するといった重要な役割を担うことになる。

著者

新井 智一

出版者

Tokyo Geographical Society

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.120, no.4, pp.676-691, 2011-08-25

被引用文献数

2

---

This paper discusses locational conflicts surrounding a new waste disposal facility in Koganei City from the viewpoint of "the politics of scale". Since 1957, Koganei, Chofu, and Fuchu cities have disposed of their waste at Nimaibashi Waste Disposal Facility. In 2007, Koganei City officials proposed the construction of a new facility by 2017 at the site of the Nimaibashi Waste Disposal Facility, which was located at the periphery of Koganei City, or at the site of a former Janome sewing machine factory, which was located at the center of the city. Although people residing near both sites protested against the construction of the new facility, the Koganei City officials decided to construct the new facility at the site of the Nimaibashi Waste Disposal Facility. The reason for this decision is summarized as follows: (1) Most of the citizens of Koganei City appeared to be indifferent to this locational conflict; (2) The Koganei City officials were adamant about constructing an incineration facility; (3) The actions of the people residing near the former Janome sewing factory, unlike those of the people residing near Nimaibashi Waste Disposal Facility, were successful in protesting given the scale of Koganei City.

著者

奥山 喜久夫

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.98, no.6, pp.775-781, 1989-12-05 (Released:2009-11-12)

参考文献数

6

被引用文献数

1

著者

平賀 岳彦

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.108, no.2, pp.110-121, 1999-04-25 (Released:2009-11-12)

参考文献数

27

被引用文献数

3 3

---

Grain boundaries in metamorphic rocks were obsereved by high-resolution transmission electron microscopy. Most of the boundaries have no distinct secondary phases at a nanometer scale. Not only between the same kind of minerals but also between different minerals, mineral grains are directly connected at their boundaries, showing that the structual width of the grain boundaries is less than 0.5nm. Grain boundaries with spheroidal voids are observed in the boundaries. It can be concluded that this type of grain boundary is formed by the healing of microcracks. Low-index plane boundaries are well-developed, showing that this type of boundary has low grain boundary energy. Local structural modification, indicating the segregation of impurities, in grain boundaries is observed. The present results show that the actual width of the grain boundary in rocks is too small for the grain boundary diffusion to be as the dominant transport mechanism.

著者

片尾 浩

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.111, no.2, pp.248-255, 2002-04-25 (Released:2009-11-12)

参考文献数

9

被引用文献数

1 1

---

In the Tamba Plateau, an earthquake swarm area in the Kinki district, Central Japan, seismicity was activated just after the Hyogo-ken Nanbu (Kobe) Earthquake (M7.3), which occurred in an adjacent area in 1995. We found that micro-earthquake activities in the Tamba Plateau corresponded to moon phase. Occurrences of micro-earthquakes increased after a new moon and a full moon during 1995 and 1996. Before 1995, such a correlation could not be found. The present study suggests a possibility that the stress change caused by the Hyogoken Nanbu Earthquake made seismicity in the Tamba Plateau sensitive to tidal forces.

著者

古川 雅英

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.102, no.7, pp.868-877, 1993-12-25 (Released:2009-11-12)

参考文献数

25

被引用文献数

15 12

---

Extensive field survey on natural radiation was conducted from 1967 to 1991 over Japan Islands. The average level of the islands was found to be 79.7 nGy/h. In general, Southwest Japan has higher level compared with the Northeast one. From the data obtained at 1304 sites of the survey, a contour map of natural radiation level in the islands was made by simple interpolations, and a geological interpretation on the distribution of the level was done by comparing the contour map with geological information. The islands were divided into four areas according to whether the level is higher or lower than the average level. The boundaries between these areas were found almost exactly coincide with major geo-tectonic lines. This feature suggests that natural radiation level is controlled mainly by distribution of granitic and volcanic rocks.

著者

遠藤 毅

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.116, no.5, pp.593-626, 2007-10-25 (Released:2009-11-12)

参考文献数

47

被引用文献数

2 4

---

The Tokyo Lowland situated in the eastern part of Tokyo Metropolis was composed of extensive paddy fields until the end of the Edo era in 1868, then became a major industrial area from the beginning of the Meiji era due to the industrialization project of the early Meiji Government. The purpose of this paper is to clarify the changes in the industrial area in the Lowland since the beginning of the Meiji era, and to investigate the recent use of former factory sites following the relocation and closing of factories since around 1960.In the early part of the Meiji era, the industrial area only occupied the western part of the Lowland, the estuary of the Sumida River, and the junction of the Shakujii River and the Sumida River, and the main factories belonged to the shipbuilding and military industries. Then, over the period of two major wars, Shino-Japanese War (1894-1895) and Russio-Japanese War (1904-1905), the industrial area continued to be enlarged. At the end of the Meiji era, in 1912, many factories were developed along canals throughout the Kohtoh Area. Furthermore, the industrial area was developed throughout the Lowland during the period straddling World War I (1914-1918) and World War II (1941-1945).Although the industrial activity in the Lowland stopped for a several years from the end of the World War II in 1945, it started again with the outbreak of the Korean War, in 1950, and advanced remarkably mainly in the heavy and chemical sectors.However, this extreme industrial development brought to the Lowland the overpopulation and the public nuisances such as air-pollution, noise, and vibration from plants and manufacturing sites. To reduce these problems, the National Government and the Tokyo Metropolitan Government took such measurements as restricting the construction of new factories and strengthening regulations on the operations of factories. The regulations to prevent public nuisances were very costly to factory operators.As a result, the number of factories in the Lowland stopped increasing around 1960, and the number decreased rapidly from 1961 to 1975 because of relocation to other countries or ceasing manufacturing operations.Many former factory sites have been converted to other uses, mainly facilities for citizens such as condominiums, general residential areas, parking lots, schools, and parks. In particular, mainly at the sites of former metal industry, timber, and chemical industries, conversion to residential quarters has been remarkable. Among the new uses changed from former factory sites, the residential use occupies more than 50%.However, the change in land use from former factory sites to a residential quarter has brought problems throughout the Lowland area such the blocking of sunlight to existing houses due to the construction of housing complexes, and soil pollution caused by past industry activity. To reduce the problem of the blocking of sunlight to existing houses, each ward government has regulated the construction of housing complexes, and to reduce the problem of soil pollution, the National Government has promulgated the Soil Contamination Countermeasures Law.In addition to these problems, the extension of the subway network to the Lowland area in recent years has promoted an expansion of the residential quarter. This rapid expansion has led to a shortage of public institutions such as elementary and junior high schools. Furthermore, most of the Lowland area is permanently below sea level due to land subsidence, although the land is protected by extensive dikes and drainage systems to prevent disasters related to high tides and flooding.It is essential to solve these problems related to land use in this Lowland area.

著者

山本 薫

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.98, no.7, pp.911-933, 1989-12-25 (Released:2009-11-12)

参考文献数

35

---

Comprehending patterns of raw material utilization for stone implements can be a key to the solution of questions concerning cultural tradition, cultural behavior, culture areas and trade in prehistoric times. The materials of stone implements reflected “knowledge of requirements (specificastion)” of the tool-makers, and this point is exemplified by stone implements of the Middle Jomon period, the Neolithic period in Japan.Patterns of raw material utilization for stone implements, at that time, were different among tool types. Evidence is presented which supports the view that Jomon people intentionally selected raw materials according to their “knowledge of tool requirements” (relating to the size and the shape of the tools). In addition, utilization of raw materials for sometypes of stone tools varied between districts. However, such differences confirmed to the intentional hypothesis.Eight types of stone implements in the Middle Jomon period, arrowheads (sekizoku), drills (ishikiri), points (sentouki, sentoujyousekki), pounding stones (tatakiishi), ground or pitted stones (suriishi, kubomiishi), querns (ishizara), roughly chipped ax-like stone tools (daseisekifu) and polished ax-like stone tools (maseisekifu), have been divided into three categories (1, 2, 3) according to the pattern of raw material utilization.Category 1 : Arrowheads, drills and points. All these are small light thin and sharp pointed tools which were made from thin flakes and hard compact silicious materials, predominantly obsidian or shale. There were two regional spheres of raw material utilization, the shale area and the obsidian area. Near the producing areas of obsidian in Chubu and Kanto districts, Jomon people tended to use this material. However, in the shale producing district, Tohoku district, Jomon people used often shale (silicious shale and hard shale).Category 2 : Pounding stones, ground or pitted stones, and querns. These stone implements are big heavy round lumpish tools which were made from round stones and primarily either andesite or sandstone. In every site in Eastern Honshu, these implements were predominantly made of one of these two rock types regardless of region. In addition, such characteristic materials used for category 1, such as obsidian and shale (silicious shale or hard shale), were rarely utilized for this category.Category 3 : Roughly chipped ax-like stone tools and polished ax-like stone tools. These are the middle weight-thickness implements for which various kinds of raw materials were used, except for obsidian and shale (silicious shale or hard shale). The typical regional patterns of raw material utilization could not be found among the sites.

著者

田島 稔

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.79, no.3, pp.139-150, 1970-06-25 (Released:2009-11-12)

参考文献数

10

---

Recently, crustal movements in the Boso and Miura peninsulas have changed their mode of previous gradual sinking after the Great Kanto Earthquake to an upheaval tendency. The phenomena attracted much notice widely and increased the interest for earthquake prediction. At this opportunity, short sketch and discussion were made about the characteristics of recent crustal activities in the south Kanto district which had mainly obtained by means of geodetic repetition surveys such as levelling, tide observation, triangulation survey, distance measurement and geomagnetic survey. A picture for explaining the outline of the feature of crustal movement and a new geodetic survey planned by G.S.I. were also briefly discussed.

著者

古川 雅英

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.100, no.4, pp.552-564, 1991-08-25 (Released:2010-11-18)

参考文献数

72

被引用文献数

5 11

---

The Ryukyu Arc-Okinawa Trough system is one of several arc-backarc systems alongthe margin of the western Pacific and east Asia. Recent results of seismic refractionand reflection studies have revealed that the origin of the trough is the continental rifting, and the trough is in a state of the active rifting stage (e. g. Hirata et al., 1991; Furukawa et al., 1991). Basement rocks and sediments to appraise for the age of the trough, however, have notbeen sampled by deep sea drilling. Then the formation age of the trough was mainlyexamined by the geological studies of the Ryukyu Arc and Okinawa Trough areas andpaleomagnetic stud -ies of the Ryukyu Arc.Geological sequence of the Ryukyu Arc is generally divided into two units, thepre-Miocene basement complex and post-middle Miocene sediments (e. g. Kizaki, 1986). Thenorth and central Ryukyu Arcs represent the geological continuation of the Outer Beltof the south west Japan Arc, composed of the Mesozoic to Eocene sedimentary sequences, whereas thesouth Ryukyu Arc is characterized by high-pressure metamorphic rocks and the Eocenevolcanics and limestone. The geological and structural contrasts between the north-central andsouth Ryukyu Arcs are conspicuous before the late Miocene. These observations suggest that theformation of the Okinawa Trough have been originated since the Miocene, and the Ryukyu Archave been established since then.Paleomagnetic studies for the the Eocene to Pliocene volcanics and sedimentscollected from the Ryukyu Arc and northeast Taiwan suggest that the south Ryukyu Arc rotatedclockwise 19° with respect to the central Ryukyu Arc and Taiwan between 10 Ma and 4 Ma.Paleomagnetic studies attribute this rotation to the opening of the southern part of theOkinawa Trough during 10 and 4 Ma (Miki et al., 1990; Miki, 1991).The acoustic sequence in the trough can be divided into three units. And the eachunit are correlated to the Pliocene to early Pleistocene, middle to late Pleistocene, and late Pleistocene to Recent sediments in descending stratigraphic order. Widespreaddeformation by normal faulting is especially developed in the lowest unit which displays horst andgraben structures. The deformation would have originated at about the Plio-Pleistoceneboundary and formed the prototype of the trough (Furukawa et al., 1991). Synthesizes of the above studies have resulted in interpretativedevelopment of the trough as follows; a major phase of formation of the trough occurred during 10 and4 Ma, and reactivation of the formation of the trough occurred after 2 Ma. Recent studies fortherifting of several continental margins, however, suggest that the intra-arc rifts evolved 10times as first as major intra-continental rifts, and the life time of the rapid rifting is onlyabout 3 to 5 Myr (Yamaji and Takeshita, 1989). The middle Pleistocene reefal limestone dredged fromsome knolls in the Okinawa Trough indicate that the subsidence of the trough was about500-1, 000m after the middle Pleistocene. As a preliminary conclusion, therefore, the age ofthe trough could be estimated to be roughly 2 Ma. The present age estimation is againstrecently proposed clockwise rotation of the south Ryukyu Arc due to the opening of thetrough from 10 Ma to 4 Ma which was reported by the paleomagnetic study.