著者

斎藤功

出版者

東京地学協会

雑誌

地学雑誌

巻号頁・発行日

vol.110, no.3, 2001

著者

松山 薫

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.106, no.3, pp.332-355, 1997-06-25 (Released:2010-04-23)

参考文献数

34

被引用文献数

4 4

---

Military establishments are special kinds of public facilities which are not oriented to common users and are under direct government control. To verify their strong spatial influence, the author reviewed a series of policies on the disposal of national properties, and studied changing land use of the former military airfields in the Kanto District.With the end of World War II, a large number of military establishments and properties all over Japan lost their functions. Many of them were released for public use and others were taken over by U.S. military. Their disposal was affected by three groups of government policies : fundamental laws on the disposal of national property exercised by the Finance Ministry; several policies on postwar reconstruction, industrial promotion, regional development, etc. ; and the occupation policies with military purposes and defense policies based on the Security Treaty between Japan and U.S.A.Based on the investigations covering 60 airfields in the Kanto District, the author has found that three stages characterize the major patterns of land use conversion.In the first stage (1945-1960), most of the former Japanese military airfields became farmlands for food supply and unemployment relief under the reclamation policy. The other airfields, especially those located closer to the metropolis, remained for military use by the U.S. Armed Forces.The second stage (1960-1975) corresponds with the period of rapid economic development, and a lot of industrial estates were developed on the former airfields. Most of them were converted from reclaimed farmlands. Another conspicuous land use emerging on the former airfields in this period was military use by the Japanese Self Defense Forces, taking over the U.S. military bases or reclaimed farmland.The third stage (1975-) is characterized by large-scale redevelopment for public purposes on the former U.S. military airfields which were returned to the Japanese Government.Although these three stages generally correspond with the Japanese socio-economic changes throughout the postwar period, some of the land use changes preceded general changes, because they were authorized by the government policies.Actual cases of the changing of land use on the 60 airfields are classified into five types : A (farmlands), B (farmlands to industrial sites), C (U.S. military to public use), D (U.S.military or Japanese Self Defense Forces), and E (farmlands or U.S. military to airfields). The average distance from the metropolis is the greatest in type A, followed by B and D. C and E are situated closest to the metropolis. Type C has had the most extensive and various spatial effects on surrounding areas. It is also worth noting that the boundaries of former military airfields can be easily identified in many cases even after land use conversion.These changes have influenced various aspects of the changing spatial structure in the Kanto District, mainly because of the land property characteristics (large-scale area, firm ground surface, land ownership with grid pattern, etc.) and historical factors (former national lands with special public facilities).

著者

中村 一明

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.93, no.1, pp.56, 1984-02-25 (Released:2010-10-13)

被引用文献数

1

著者

荒川 秀俊

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.60, no.4, pp.167-172, 1951-12-30 (Released:2009-11-12)

参考文献数

2

---

As the appropriate level for the balloon bombs 10-12 km level has been selected, for the level is the barotropic surface with maximum westerly currents. During the winter 1944-1945, many balloons were sent to United States from Japan, for this period is characterized by heavy baroclinicy in the middle latitudes and hence the greatest strength of the westerlies is found in winter. Two or three days will be enough to send balloons through the upper troposphere, if the conditions are favourable.

著者

松岡 憲知 池田 敦

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.120, no.3, pp.502-535, 2011-06-25 (Released:2011-09-06)

参考文献数

160

被引用文献数

4 2

---

Spacio-temporal variability of contemporary periglacial environments in the Swiss Alps is summarized on the basis of 15 years of field observations of rock weathering, permafrost creep, and soil movements, as well as other recent studies. Diurnal and annual freeze-thaw cycles loosen wet rock joints, which subsequently produce rockfalls. A large episodic rockfall can temporarily raise the rate of rockwall retreat. Rock debris derived from different parent rocks controls the types of rock glacier having different compositions, thermal characteristics, and dynamics. Some rock glaciers at the lower limit of permafrost are accelerating due to intensified mobility, but they may eventually become inactive because of permafrost thawing and the lack of debris supply. On slopes mantled with fine debris, small-scale stripes and lobes tend to develop on the upper part due to thin debris and good drainage, whereas larger scale lobes increase downslope as a result of thicker debris, poor drainage, and gentler slopes. The former mainly responds to shallow diurnal freeze-thaw cycles, whereas the latter reflects frost heave and gelifluction during deeper annual freezing-thawing. A prolonged supply of meltwater further triggers rapid mudflows superimposed on slow solifluction. Climate warming may decrease periglacial activity in seasonal frost areas, whereas in marginal permafrost areas it promotes permafrost warming that temporarily accelerates permafrost creep and/or permafrost thawing that possibly triggers large rockfalls and debris flows.

著者

ジェームズ・ ドーム 丸山 茂徳

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.127, no.5, pp.609-618, 2018-10-25 (Released:2018-11-14)

参考文献数

32

被引用文献数

2 2

---

Habitable Trinity is a new concept for a habitable environment proposed by Dohm and Maruyama (2015). This concept indicates that the coexistence of an atmosphere, an ocean, and a landmass, accompanied by a continuous circulation of material among these three components driven by the Sun, is one of the minimum requirements for life to emerge and evolve. Because a life body consists of carbon (mainly from the atmosphere), oxygen (mainly from an ocean), hydrogen (mainly from an ocean), nitrogen (mainly from the atmosphere), and various nutrients (supplied from a landmass), the presence of water alone is not a sufficient condition. The Habitable Trinity concept can also be applied to other planets such as Mars, Europa, and Titan, and even exoplanets, as a useful index in the quest for life-containing planetary bodies.

著者

吉原 新

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.114, no.2, pp.212-222, 2005-04-25 (Released:2009-11-12)

参考文献数

52

被引用文献数

1 1

---

Knowledge of the Earth's magnetic field during Archean and Proterozoic times can provide important sources of information for understanding the internal and environmental evolution of the Earth. The long-term variation in field intensity and reversal rate is considered to reflect mode changes in powering the geodynamo. Several recent efforts to reconstruct the magnetic field of the early Earth have reported relatively low to moderate field accompanied by occasional polarity reversals. The volume of reliable paleomagnetic data, however, is still insufficient to characterize its long-term nature. Here, recent paleointensity and paleodirectional studies on Archean and Proterozoic rocks including our new findings are reviewed, and their problems and further perspectives are argued.

著者

磯崎 行雄 笠原 順三

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.112, no.2, pp.185-186, 2003-04-25 (Released:2009-11-12)

著者

カーシュビンク ジョセフ L. ワイス ベンジャミン P.

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.112, no.2, pp.187-196, 2003-04-25 (Released:2010-04-23)

参考文献数

49

被引用文献数

5 7

---

Recent paleomagnetic studies on the Martian meteorite ALH84001 have shown that this rock traveled from Mars to Earth with an internal temperature entirely below 40°C. Dynamical studies indicate that the transfer of rocks from Mars to Earth (and to a limited extent, vice versa) can proceed on a biologically-short time scale, making it likely that organic hitchhikers have traveled between these planets many times during the history of the Solar system. These results demand a re-evaluation of the long-held assumption that terrestrial life. first evolved on Earth, as it could just as easily have evolved on Mars and traveled here. We argue here that the chemical environment on early Mars would have been better for the evolution of early biochemical reactions than that of early Earth.

著者

磯崎 行雄

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.114, no.3, pp.410-418, 2005-12-25 (Released:2009-11-12)

参考文献数

14

---

Current trends in research on history of life are briefly reviewed. Since the 1990s study on deep past focusing on early life on Earth and Mars has become popular. This trend often called astrobiology will be a main stream in earth science in this century because it involves the latest human issues, such as global environment, energy, food, world population, and search for habitable planets outside the solar system, in addition to conventional studies on the evolution of Earth and life. Studies on chemofossils of nanometric scale and on geochemical proxies for evaluating paleoenvironments will be the most important targets in this research field. Inevitable in Japan are overhaul of the current domestic-oriented atmosphere in the geological community and deployment of a new research style under a long-term scope.

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.1, no.5, pp.216-217, 1889-05-25 (Released:2010-12-22)

著者

堤 之恭 沢田 輝 磯﨑 行雄

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.127, no.5, pp.723-734, 2018-10-25 (Released:2018-11-14)

参考文献数

47

被引用文献数

3 3

---

Zircon is the only candidate of Hadean terrestrial material that can be collected because it can survive physically and chemically, as well as maintain its U–Pb age system during omnigenous geological events. However, Hadean zircons are rare, so many age analyses of zircons are required to isolate Hadean zircon grains. There are two ways to improve the analyses; decrease the time required for pre-analyzing processes and decrease the time required for age analysis. New equipment, high-voltage pulse power fragmentation device and automatic zircon pick-up system are effective for crushing rock sample and separating zircon grains, respectively, in a short time. Another potential age analysis, the 207Pb/206Pb age screening analysis, shows good performance in selecting old zircons quickly. Integrative operation of equipment and methods will result in successfully finding numerous Hadean zircons.

著者

道林 克禎

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.117, no.1, pp.93-109, 2008-02-25 (Released:2010-02-10)

参考文献数

74

被引用文献数

9 9

---

Peridotites derived from the uppermost mantle consist dominantly of olivine and subsequently of pyroxene, spinel, garnet, and plagioclase. Crystal-plastic flow of mantle rocks results in various types of structure within peridotite being developed to varying degrees, depending upon the structure sensitivity of the different mineral phases. Plastic deformation leads to the simultaneous development of shape-preferred orientations and crystal-preferred orientations. A shape-preferred orientation is the expression of the average orientation of flattening (foliation) and elongation (lineation) directions, as defined by the orientations of individual grains. A crystal-preferred orientation (CPO) is the expression of crystallographic orientations of grains within the rock, as developed via dislocation creep and recrystallization. During intense homogeneous plastic deformation of a peridotite composed of minerals with a dominant slip system, the preferred orientation of the slip plane and slip direction tends to coincide with the plane of plastic flow and the flow direction, respectively. Recently, a new olivine CPO classification (A, B, C, D, and E types) has been proposed by Karato and co-workers to illustrate the roles of stress and water content as controlling factors of olivine slip systems. An additional CPO type (AG) has also been proposed in recognition of its common occurrence in nature. Given that olivine and the other constituent minerals in peridotites contain intrinsic elastic anisotropies, the development of CPO within peridotite during plastic deformation gives rise to seismic anisotropy in the upper mantle. Thus, the anisotropic properties of mantle rocks derived from the upper 100 km of the mantle, such as Ichinomegata peridotite xenoliths from the northeast Japan arc, have been calculated and applied with the aim of understanding the seismic anisotropy of the Earth's mantle.

著者

新谷 俊一 田中 和広

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.118, no.3, pp.340-349, 2009-06-25 (Released:2010-03-26)

参考文献数

20

被引用文献数

12 12

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Mud volcanoes are structures formed as a result of the emissions on a land surface or the sea floor of argillaceous material, which is composed of erupting remobilized mud, petroliferous or magmatic gases, and high-salinity water. Recently, large constructions have been planned deep underground besed on the expectation of geological stability. Therefore, it is important to study the origin of erupted mud and groundwater and the depths from which they ascend when evaluating long-term stability. Three active mud volcanoes and a passive mud volcano are found in the Tertiary Shiiya Formation distributed in Tokamachi City, southern part of Niigata Prefecture. Detailed descriptions of the mud volcanoes are provided by Shinya and Tanaka (2005). However, the origin of erupted mud and the formation mechanism of abnormal pore water pressure have not yet been identified. The authors measured the oxygen and hydrogen isotopic ratio of groundwater and vitrinite reflectance of coal fragments separated from erupted mud of an active mud volcano to investigate the origin of erupted mud, particularly the depth of the origin, and the formation mechanism of abnormal pore water pressure. As a result, δ18O and δD values of erupted water are 1.2‰, -5‰ respectively, showing good agreement with those of the Nanatani Formation distributed at a depth of 3400 m in depth in the studied area. Vitrinite reflectance (Ro) shows a bimodal distribution (i.e., 0.3-1.2% and 1.5-1.8%). Ro value of coal fragments sampled from the Shiiya Formation at the outcrop in the studied area are 0.3-0.45%. High Ro (1.5-1.8%) values of coal fragments are obtained in core samples at a depth of 4000 m in the Gimyo SK-1 oil well, which was excavated 2 km NW from the mud volcano. As a result of an investigation of erupted materials at the mud volcano, they were found to have originated at depths of from 3400 m to 4000 m in the studied area. Geothermal temperature of underground at depth of 3400 m to 4000 m in the in the studied area is estimated to be about 120°C to 150°C. Estimated temperature is high enough to cause diagenetic transition from smectite to illite. Transition from smectite to illite results in the release of a large volume of pore water into the sediment. It is concluded that dehydration due to mineral transition might be the major reason for abnormal pore water pressure formation at depths of 3500 m to 4000 m in the study area.

著者

村上 亮 飛田 幹男 矢来 博司 小澤 慎三郎 西村 卓也 中川 弘之 藤原 智

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.109, no.6, pp.944-956, 2000-12-25 (Released:2009-11-12)

参考文献数

23

被引用文献数

1 1

---

The power of interferometric Synthetic Aperture Radar (SAR) when applied to studies of crustal deformation has been fully demonstrated by Massonnet et al. (1993, 1994) and Zebker et al. (1994) for the Landers, California earthquake of June 28, 1992. This method is unique in its capability of providing a two-dimensional representation of a deformation with a dense spatial coverage over most of the globe. Since 1994, the Geographical Survey Institute (GSI) has been conducting a study on applications of differential InSAR (Interferometric SAR) for the detection of crustal deformations associated with earthquakes and volcanic activities. Crustal deformations of many episodes were mapped by InSAR, such as those due to the 1994 Northridge earthquake, the 1995 Hyogo-ken Nanbu earthquake, the 1995 Neftegorsk earthquake, and volcanic deformations of Mt. Iwate and Mt. Usu. These interferograms played an important role in constructing geophysical models.

著者

岩森 光

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.174-187, 2007-02-25 (Released:2009-11-12)

参考文献数

56

被引用文献数

1

---

To understand the transportation and the circulation of water in subduction zones and the mantle, the maximum H2O content of rocks under variable pressure-temperature conditions was reviewed. The maximum H2O content is also important for assessing the potential storage of H2O in the mantle, which shows that the mantle can contain 4.6 to 12.5 times more H2O than the current ocean mass, assuming a standard geothermal gradient. Although the estimation has a large degree of uncertainty, the mantle is a significant storage, and plays an important role in global water circulation, especially due to the unexpectedly high capacities of nominally anhydrous minerals (NAMs). Based on this information, water circulation in subduction zones (especially in the Japanarcs) and the mantle has been discussed with the relevant numerical modeling and geophysical and geological observations. Consequently, the following points have been clarified : (1) breakdown depths of the major hydrous minerals within and around the subducting slab depend on the thermal structure (deeper for colder environments); (2) when a hot slab, including a spreading mid-ocean ridge, subducts, both water and heat are supplied to the forearc region, contributing to the formation of regional metamorphic belts; (3) both high-pressure-type and high-temperature-type metamorphism occur within a limited time in a single forearc domain associated with ridge subduction ; (4) arc magmatism and regional metamorphism are regarded as a series of geological events corresponding to different stages of a temporal change in the thermal state of a subduction zone; (5) although major dehydration of subducting slabs occurs at depths shallower than 200 km, triggering arc magmatism or regional metamorphism, the subducting slab and the bottom portion of the overlying mantle wedge above the slab transport several 100 to several 1000 ppm of H2O with NAMs to the transition zone ; (6) the influx of H2O into the transition zone by this mechanism is comparable to or exceeds outgassing by magmatism at mid-ocean ridges and hotspots; (7) the influx was suppressed in the past where the potential temperature was high (hot-dry regime), while it will be enhanced in the future as the Earth cools (cold-wet regime), resulting in stabilization and prolongation of mantle convection; and, (8) considering the presence of very cold subduction zones such as central Japan, where a significant amount of water is exceptionally transported to the deep mantle, the present-day Earth is probably in a transition from a hot-dry regime to a cold-wet regime. In any case, the maximum H2O content in NAMs in the upper mantle controls the influx, which needs to be constrained tightly for more accurate estimations of global water circulation.

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.49, no.9, pp.443, 1937-09-15 (Released:2010-12-22)

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.131, no.3, pp.Cover03_01-Cover03_02, 2022-06-25 (Released:2022-07-08)

参考文献数

2

---

西南日本から連続する中央構造線(MTL)は,群馬県西部下仁田地域を通過し,北側に領家帯の白亜紀花崗岩類や美濃・丹波帯(=足尾帯)のジュラ紀付加体が,南側に三波川帯の白亜紀高圧型片岩が広く露出する.MTLのすぐ南側には,低角度断層を介して三波川変成岩の上に特異な岩石・地層群がクリッペとして累重する.「跡倉クリッペ」はペルム紀花崗岩やホルンフェルス,非変成の白亜系–古第三系礫岩・砂岩など,どれも少量だが多様な岩石から構成される.1950年代から研究されはじめたが,その起源は長らく謎であった.写真は,下仁田南方の南牧川沿いに露出する逆転した跡倉層の下部白亜系砂岩・泥岩交互層である.近年,同層を含む関東山地の白亜紀砂岩中の砕屑性ジルコンのU–Pb年代が測定され(中畑ほか, 2015, 2016),跡倉層には原生代(25-15億年前)粒子が大量に含まれることが判明した.同じ関東山地でも約10 km南方の秩父帯の同時代砂岩とは大きく異なる後背地をもつこと,また西南日本では飛騨帯と舞鶴帯にのみ知られるペルム紀花崗岩を随伴することから,跡倉クリッペは関東でできた岩石群ではなく,もともと中生代日本の大陸側に起源をもち,二次的に長距離(最大100 km程度)移動してきた岩体と推定される.こんにゃくとネギで有名な下仁田地域の地質には,日本列島のルーツに関する秘密が隠されている.地元を走る上信電鉄の車体に大きくペイントされた「跡倉クリッペ」の文字をみて嬉しくなるのは「撮り鉄」ファンだけではないだろう.(写真・解説:磯﨑行雄)

著者

苅谷 愛彦 佐藤 剛 小森 次郎

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.117, no.3, pp.xv-xvi, 2008-06-25 (Released:2010-05-14)

著者

ビルンド エリック 岩田 修二

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.90, no.2, pp.112-121, 1981-04-25 (Released:2010-11-18)

被引用文献数

1

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フィンランド・ノルウエー・スウェーデンの北部に35, 000人ほどいるラップ人のうち, 山地の森林限界以上に居住する山地ラップ人と, 低地の森林に居住する森林ラップ人とは, 暮らし方がかなりちがっている。森林ラップ人の生活は古い時代のラップ人の生活様式を色濃く残している。ごく最近まで, 森林ラップ人は狩猟や漁労 (これらはラップ人の古い生業形態である) を生業にしていた。トナカイの飼育を始めたのは最近で, 飼っている頭数も少なく, 移動範囲もせまい。山地ラップ人が牧畜を始めたのもそれほど古いことではなく, 16-17世紀である。そして, およそ100年前には完全に牧畜(移牧)だけに依存するようになった。夏には高山地域へ, 冬には森林地域へ移動し, 春と秋は亜高山帯で過す。移動距離は数100kmにも達している。山地ラツプ人の生活基盤は牧畜業にあると考えられがちであるが, 現在では牧畜だけで生活しているラップ人の数はたいへん少数になった。スウェーデンの場合, ラップ人口のうちの7%ないし25%にすぎない。17世紀後半には, ラップランドにはラップ人だけが居住していた。そこへ, 南からの移住農民が侵入するにつれて, いろいろの問題がおこり始めた。これに対する政府の立場は, スウェーデンの場合, 土地は広大であり, 移住農民と牧畜ラップ人とは生活の場が異なるから摩擦は起きないであろうというものであった。しかし, 現実には多くの問題が起き, ラップ人はいつも不利益をこうむってきた。政府が長年ラップ人を保護し, 生活水準・教育水準を高めてきたとはいうものの, 少数民族であることと, 牧畜という不安定な生業に依存していることとのために問題の根本解決はなされていない。ラップランドからの人口流出が20世紀半ばから始まったことによって, ラップ人がラップランドとその周辺でスウェーデン人に雇用される機会が減った。いっぽう, ラップ人に対する人種偏見は減り, ラップ人がスウェーデン社会にとけこみやすくなった。しかし, これがラップの固有文化の崩壊をはやめることになった。現在では都市で生活しているラップ人も多い。