著者

淺香 幸雄

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.46, no.6, pp.292a-295, 1934-06-15 (Released:2010-10-13)

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.108, no.4, pp.Plate1-Plate2, 1999

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.20, no.1, pp.59a-60, 1908

著者

山田 周二

出版者

Tokyo Geographical Society

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.110, no.1, pp.79-93, 2001-02-25

被引用文献数

1 1

---

This study classified Japanese mountains based on mountain ordering using 1 : 500000 topographic maps, and examined the relationships of relief, relative relief and perimeter fractal dimension for the classified mountains. Mountain order was defined in terms of closed contour lines on the topographic map. A set of closed, concentric contour lines defines a first-order mountain. Higher-order mountains can be defined as a set of closed contour lines that contain lower-order mountains and that have only one closed contour line for each elevation. Relief, relative relief and fractal dimension were measured for ordered mountains using personal computer, and were defined as follows : relief <I>E = H/A</I><SUP>1/2</SUP>, where <I>H</I> and <I>A</I> are the height and area of each ordered mountain, respectively; relative relief <I>R</I>= ∑ <I>h<SUB>i</SUB>/H</I>, where <I>h<SUB>i</SUB></I> is the height of the enclosed, lower-order mountains, and represents the degree of vertical roughness of the ordered mountain; fractal dimension was measured for perimeter contour line by the pixel dilation method, and represents the degree of horizontal roughness of the ordered mountain. Japanese mountains were classified into 74 third order mountains and 11 fourth order mountains. The area of a third order mountain varies from 50 to 4712 km<SUP>2</SUP>, and that of a fourth order mountain is 2498 to 15563 km<SUP>2</SUP>. A significant relationship was found among relief <I>E</I>, relative relief <I>R</I>, and fractal dimension <I>D</I> for the ordered mountains (r=0.91, n=85), and can be defined by the expression : <BR>Log<I>E</I>=-a<I>D</I>-bLog<I>R</I>-c<BR>This relationship shows that Japanese mountains have the following morphological characteristics : a high relief mountain has low vertical and horizontal roughness, and a low relief mountain has high vertical and horizontal roughness. These characteristics suggest that slope angle of Japanese mountains converges within a certain range.

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.19, no.7, pp.513-513, 1907-07-15 (Released:2010-12-22)

著者

Y C

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.33, no.4, pp.230a-231, 1921

著者

小野 昭

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.111, no.6, pp.840-848, 2002-12-25 (Released:2009-11-12)

参考文献数

18

被引用文献数

1 1

---

A framework of climatic changes and archaeological chronologies during the Last Glacial is discussed with particular reference to the correlation among MIS stages, GISP2 ice core oscillation, and calibrated radiocarbon dates from palaeolithic sites in Rhineland, Germany as one of the most intensively studied areas in Central Europe. Although the fine chronologies have been set up in the last decade, an analysis of a concrete example of a palaeollithic site is needed when hominid adaptation in the Last Glacial has to be discussed. This paper focuses on the subsistence of a late Magdalenian Gennersdorf settlement in the oldest Dryas period. Excavations have revealed two large houses, one big hut, and two small huts. Archaeological features that have been well preserved made it possible to set out a hypothesis that the large house was repeatedly used every winter and the small huts were used in summer by different human groups, in relation to the lithic raw material, procurement systems. Hominids of the late Palaeolithic period were characterized by having developed a subsistence system for the all round adaptive procurement of environmental conditions through seasonal migrations.

著者

川本 竜彦

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.124, no.3, pp.473-501, 2015-06-25 (Released:2015-07-10)

参考文献数

165

被引用文献数

2 2

---

Subduction-zone magmatism is triggered by the addition of H2O-rich slab-derived flux: aqueous fluids, hydrous partial melts or supercritical fluids from the subducting slab through reactions. Whether the slab-derived flux is an aqueous fluid, a partial melt, or a supercritical fluid remains an open question. In general, with increasing pressure, aqueous fluids dissolve more silicate components and silicate melts dissolve more H2O. Under low-pressure conditions, those aqueous fluids and hydrous silicate melts remain isolated phases due to the miscibility gap. As pressure increases, the miscibility gap disappears and the two liquid phases becomes one phase. This vanishing point is regarded as critical end point or second critical end point. X-ray radiography experiments locate the pressure of the second critical end point at 2.5 GPa (83 km depth) and 700°C for sediment-H2O, and at 2.8 GPa (92 km depth) and 750°C for high-Mg andesite (HMA)-H2O. These depths correspond to the depth range of a subducted oceanic plate beneath volcanic arcs. Sediment-derived supercritical fluids, which are fed to the mantle wedge from the subducting slab, may react with the mantle peridotite to form HMA supercritical fluids due to peritectic reaction between silica-rich fluids and olivine-rich mantle peridotite. Such HMA supercritical fluids may separate into aqueous fluids and HMA melts at 92 km depth during ascent. HMA magmas can be erupted as they are, if the HMA melts segregate without reacting to the overriding peridotite. Partitioning behaviors between aqueous fluids and melts are determined with and without (Na, K) Cl using synchrotron X-ray fluorescence. The data indicate that highly saline fluids effectively transfer large-ion lithophile elements. If the slab-derived supercritical fluids contain Cl and subsequently separate into aqueous fluids and melts in the mantle wedge, then such aqueous fluids inherit much more Cl and also more or less amounts of large ion lithophile elements than the coexisting melts. In contrast, Cl-free aqueous fluids can not effectively transfer Pb and alkali earth elements to the magma source. Enrichment of some large-ion lithophile elements in arc basalts relative to mid-oceanic ridge basalts has been attributed to mantle source fertilization by such aqueous fluids from a dehydrating oceanic plate. Such aqueous fluids are likely to contain Cl, although the amount remains to be quantified. If such silica-rich magmas survive as andesitic melts under a limited reaction with mantle minerals, they may erupt as HMA magmas having slab-derived signatures.

著者

高井 研 稲垣 史生

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.112, no.2, pp.234-249, 2003-04-25 (Released:2009-11-12)

参考文献数

82

被引用文献数

5 2

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Seafloor hydrothermal system and deep subsurface are of great interest for microbiologists as paradise of unusual lives so-called “Extremophiles” in this planet. Such peculiar microorganisms have been believed to be minority in the earth throughout the long history after the early evolution of life. Recent investigations for microorganisms present in the active hydrothermal seafloor and subsurface have revolutionized the concept. Ubiquity, predominance and diversity of extremophiles in the present and past global environments signify the unresolved, but significant role in the co-evolution of earth and life. In this article, we summarize the expeditions for the microbial world in the seafloor hydrothermal system and deep subsurface and shed light on the foci of the future investigation.

著者

岩崎 重三

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.21, no.5, pp.353-356, 1909

著者

大森 房吉

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.32, no.4, pp.172-180, 1920

著者

早川 由紀夫 新井 房夫 北爪 智啓

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.106, no.5, pp.660-664, 1997-10-25 (Released:2009-11-12)

参考文献数

10

被引用文献数

1

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The Edifice of Hiuchi Volcano was founded on the Mokake ignimbrite plateau which is directly underlain by the Nanairi pumice. They erupted from near the present summit successively about 350ka. On the plateau, the Ozorizawa cone was first established about 100 ka. Next, the Shibayasugura cone having twin peaks, Shibayasugura (2, 356 m) and Manaitagura (2, 346 m), was built shifting slightly southeast. At 19ka, the Jubeike lava flow and Kumazawa Tashiro lava dome were issued from the northeastern flanks. The latter was accompanied by a devastating blast. Southward-opening horseshoe depression is source of the Nushiri debris avalanche, which dammed up the Nushiri River and formed the Oze marsh about 8ka. The Akanagure lava dome and flows immediately occupied the depression. The youngest volcanic feature at Hiuchi is the Miike lava dome, 300m south of the Manaitagura peak. It emplaced during the 16th century, just before the Shirohikemizu flood descended the Hinoemata River on July 28, 1544. Hiuchi Volcano has erupted 17 × 1012 kg of magma since its birth, 350 thousand years ago. Average discharge rate is 4.9 × 1010 kg per thousand years, an order of magnitude smaller than that of the most active Japanese volcanoes.

著者

本多 啓太 須貝 俊彦

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.119, no.5, pp.924-933, 2010-10-25 (Released:2011-01-21)

参考文献数

82

被引用文献数

3 3

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In warm-humid and tectonically active regions such as Japan it is important to investigate the geomorphic development of recent alluvial plains controlled by sea-level changes to prevent natural disasters. This is because human activities concentrate coastal alluvial plains composed of unconsolidated soft sediments (alluvium) including inner-bay mud, which amplify seismic intensity. However, we know little about the general shape of the alluvium quantitatively although several river basins have been investigated in detail. We selected 33 trunk rivers throughout Japan and measured the Present River long-Profile (PRP) along with the Last Glacial River long-Profile (LGRP) defined by the depositional surface of basal gravel layers formed under the influence of falling sealevels during the last glacial period. The thickness of the alluvium given by the relative altitude between PRP and LGRP was basically in proportion to the size of the river basin, and it decreased linearly upstream with the exception of several rivers such as Shinano, Kiso, Oita, and Yoshino. Along these rivers, the alluvium is markedly thicker than expected probably because of tectonic subsidence occurring repetitively after formation of basal gravel layers. This implies that the fluvial response to sea-level change is sensitive enough to distinguish the effects of the accumulation of tectonic movements after deposition of basal gravels. In stable or slightly uplifted areas, the inland distribution of inner-bay mud is basically controlled by river basin size.

著者

宮縁 育夫

出版者

公益社団法人 東京地学協会

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.125, no.3, pp.421-429, 2016

被引用文献数

18

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The Kumamoto earthquake(Mj7.3) on April 16, 2016 triggered numerous landslides in and around Minamiaso Village, which is located at the western part of Aso caldera, southwestern Japan. The landslides were divided into two types:landslides occurring at steep caldera walls and landslides generated on the slopes of post-caldera central cones of Aso Volcano. Several landslides occurred on slopes steeper than 25°at the northwestern to western caldera walls, which comprise pre-Aso volcanic rocks (lavas and pyroclastics). The largest landslide (ca. 300m high, 130-200m wide) occurred on the western caldera wall, damaging National Route 57 and the Hohi line of the Japan Railway. Because a clear rupture surface could not be observed, unstable blocks which had been divided by cracks, were likely to collapse due to the intense earthquake on April 16. At the post-caldera central cones of Aso Volcano, earthquake-induced landslides were generated not only on steep slopes but also on slopes gentler than 10°. They occurred in unconsolidated superficial tephra deposits overlying lavas and agglutinates, and the thickness of the slides usually ranged from 4 to 8 m. The sliding masses traveled long distances (<600m), compared to small differences in elevation. The deposits were composed of tephra blocks of a few meters and there was no evidence that they were transported by water. These facts suggest that some landslides mobilized rapidly into debris avalanches, traveling a few hundred meters. The associated debris avalanche resulted in five casualties and severe damage to houses at the foot of the Takanoobane lava dome. The characteristics of the April 16, 2016 earthquake-induced landslides differ from those of rainfall-induced landslides in July 2012, June 2001, and July 1990 at Aso Volcano, and provide important imformation for preventing or mitigating future landslide disasters in the Aso caldera region.

著者

吉川 清志

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.99, no.7, pp.743-758, 1990-12-25 (Released:2009-11-12)

参考文献数

32

被引用文献数

9 18

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Inductively coupled plasma emission spectrometry (ICP) is applied for the chemical analyses of volcanic glasses to improve the efficiency of identification of widespread tephra.The differences of specific gravity and magnetic property among glass and minerals are effective for purification.The ICP method is very useful for routine analyses. The values of chemical analysis by the ICP are close to the EPMA data. The reproducibility is exellent, while fluctuation coefficients of most elements of tephra are about 5 %. Good correlations are found between the sum of major elements except of SiO2 and the refractivity of glass, and between the Fe/Mg ratio and the refractivity of orthopyroxene.Unique tephra in middle Pleistocene can be classified into two different groups of tephra by their minor elements Y and MnO. Tephra in north eastern Hokkaido are mainly came from two sources, which can not be distinguished in the field. The contents of incompatible elements of two types of tephra are clearly different. The source regions of Pliocene to Pleistocene tephra in Tokai and Kinki area can be estimated by the regional characteristics of their chemical compositions. The ICP method is also successfully applied for identification of submarine tephra in eastern Japan Sea, and correlation of sediments of Kanto to Kyushu areas and discovery of source of some widespread tephra in early to middle Pleistocene.

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.36, no.9, pp.558a-558a, 1924

著者

ホッペ グンナー 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.85-92, 1981

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せまい地域から地球的規模までの自然の理解や環境悪化の監視のための重要な方法であるリモートセンシング技術の最近の発展はたいへんめざましい。この技術がもっとも有効に利用されているのは低緯度地域においてであるが, 高緯度地域においても有効な技術であることはいうまでもない。<BR>米・ソの二大国が主導的な位置をしめるリモートセンシングの技術開発のなかにあって, スウェーデンは, ハッセルブラッドのカメラシステムとAGA赤外テレビシステムの開発という2つの重要な貢献をしている。<BR>スウェーデンにおける空中写真の利用は80年前に始まり, 氷河調査, 地形図・土地利用図の作製, 森林管理, 地形・地質の調査などに役立つてきた。空中写真利用の最近の興味深い例には, 北西スウェーデン山岳地域の開発計画のための組織的な空中写真判読作業や, 赤外カラー写真を利用した沿岸地域における海底地形図の作製, 森林帯における樹木の活性度の判定がある。空中写真の情報を数値化する試みも古くからおこなわれ, いくつかの映像読みとりシステムが開発された。また, 可視光と近赤外以外の波長域をカバーする装置も開発された。1973年には, リモートセンシング5力年計画として以下のものがとりあげられた。各種のセンサーを用いる全天候型のオイルもれ検知システム, 各国との協力で多様な方法を用いる海氷探知計画, マルチスペクトルスキャナーを用いた完全自動植生図化作業, レーザーを用いたばい煙検知システム。<BR>スウェーデンは人工衛星によるリモートセンシングにも古くから関心をもっていた。気象衛星の利用, ランドサットの映像の地質調査への応用などに始まって, 最近ではマルチスペクトルデーターを森林管理のために利用するためのコンピューターシステムが開発された。さらに, 土地利用地図のための自動図化装置の開発, バルチック海の生態系の解明のための技術開発などがおこなわれている。最近の重要な前進は, スウェーデン北部に衛星受信基地の建設が決定されたことである。あらたに始まろうとしている第二次5力年計画では, 将来打ちあげられる人工衛星からの情報の高度な利用が計画されている。なかでも, 1984年にフランスから打ちあげられる予定の衛星に対しては, スウェーデンも費用を負担しており, 高度な利用が期待されている。

著者

丸山 浩明 仁平 尊明

出版者

Tokyo Geographical Society

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.114, no.1, pp.68-77, 2005-02-25

被引用文献数

1 1

著者

吉村 稔

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.102, no.2, pp.131-143, 1993-04-25 (Released:2010-11-18)

参考文献数

12

被引用文献数

4 14

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In order to reconstruct the march of climate before instrumental observations in Japan, Historical Weather Data Base has been constructed. Weather descriptions in historical documents, such as official diaries of Feudal Clans in Edo Era, or of local offices in each clan, are objects of the data base. Other descriptions are in those diaries of large temples, large shrines and large farmers, and in some of private diaries Considering the description of weather phenomena in old diaries, they were grouped into 13 weather conditions In this data base, “weather range” means weather conditions in a day. A rough tendency of the weather in a day (HN), or remarkable conditions such as hot, cold, dry and wet (HT), are also important to understand weather conditions for each day. Accompanied phenomena (TK) and wind conditions (KT, TT, KH) are also objects to encode. Daily weather records for the years from 1700 to 1889 are mainly under collections. So far, more than 2, 500 years weather records have been inputted in the daily data base. The main files of the system are PC-DA (paleo climatic data), and PC-REC (paleo climatic record). The former consists of encoded weather data which will be used chiefly to retrieve weather conditions and to draw maps or to make tables. The latter contains weather descriptions in each day with Katakana, one of the Japanese characters. This will support detailed investigationAs an index of wet or dry condition for each month, “PI” is proposed. Weather conditions having some relations with precipitation are grouped to three kinds. Monthly frequencies of each type are multiplied by constants. These are 1 for “little rain”, 2 for “rain” and 5 for “much rain”. The total value in each month in each day is “PI”, which is useful for the comparison within the same daily series. The scatter diagrams of PI in Kokura Kita Kyushu City and Precipitation at Moji for each season are shown in Fig. 4. Time series of PI in 6 cities show the existence of different march in summer precipitations over Japan (Fig. 5). The monthly conditions in summer months from 1781 to 1789 are reconstructed in Fig. 6.

著者

渡辺 満久 齋藤 勝

出版者

Tokyo Geographical Society

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.115, no.6, pp.727-736, 2006-12-25

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The eastern margin of Echigo Plain, central Japan, is characterized by NNE-SSW trending active faults. The Anchi fault is made up of two segments : the Anchi-nishi fault and the Anchi-higashi fault. Each fault trace is approximately 2-km long. They may be short subsidiary faults on the hanging wall of the master fault in this region (the Tsukioka fault). Trench investigations across the Anchi fault reveal its rupture history as follows : 1) the Anchi-nishi fault and the Anchi-higashi fault are west-dipping reverse faults; 2) the Anchi-nishi fault shows a vertical offset of 1.3-1.9 m after ca. 30 ka; and, 3) the vertical displacement of 3.5 m is associated with two faulting events along the Anchi-higashi fault, one between ca. 30 and 60 ka and the other younger than ca. 30 ka. Geomorphic features indicate that a reverse fault branches into these two faults at a certain depth. Thus, the total vertical offset for the last ca. 30 ky is between 3.1 to 3.7 m. This value is one third of that along the master active fault. If the source fault consists of these active faults, we should evaluate the activity of the master fault taking account of the activity of the Anchi fault. It is very important to know the nature of subsidiary faults, even if they display very short traces.