著者

日本地学史編纂委員会 東京地学協会

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.878-889, 1993-12-25 (Released:2010-04-23)

参考文献数

19

被引用文献数

2

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.132, no.3, pp.Cover03_01-Cover03_02, 2023-06-25 (Released:2023-07-07)

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紀伊半島南部に分布する古第三系~新第三系の牟婁(むろ)層群佐本川(さもとがわ)層は,四万十帯南帯の付加体を構成する砂岩・泥岩互層である.そのなかには堆積物がまだ未固結時に形成されたさまざまな規模の褶曲構造が見られる.写真は和歌山県西牟婁郡すさみ町口和深(くちわぶか)付近の海岸で観察される褶曲の好例である.かつて重力性のスランプ褶曲と考えられていたが,場所によって褶曲軸の倒れる方向が正反対のものもあることから,現在では付加体形成時の高間隙水圧下で形成された構造と判断されている.とくに目を引くこの褶曲露頭は,付近の小字(こあざ)の地名である天鳥(あまどり)にちなむ「フェニックス褶曲」という愛称をもつ.中央の「>」状褶曲上部の水平部分の長さは約5 mあり,迫力のある景観を提供している.ちなみに,この露頭を観察するためには,事前に南紀熊野ジオパークセンターを通じてガイドツアーに申し込む必要がある.(写真・説明:小松原純子 2023年3月28日撮影)

著者

李 盛源 田瀬 則雄

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.132, no.3, pp.231-246, 2023-06-25 (Released:2023-07-07)

参考文献数

41

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The remediation effects of a permeable reactive barrier (PRB) using sulfur-limestone are investigated. The results show that highly concentrated NO3− (133-180 mg/L) in shallow groundwater decreased below the detection limit within the PRB. This phenomenon was maintained for approximately 300 days; therefore, the remediation effects within the PRB and its durability are demonstrated. It is suggested that the remediation effects due to the PRB are not solely restricted to the area within the barrier, because the decrease in NO3− extended 4.0 m downstream. Furthermore, the results of ORPSHE, δ15N, and isotopic fractionation factor (ɛ) indicate that a reductive condition forms within the PRB, where sulfur-oxidizing denitrifying bacterium preferentially exists. Before installing the PRB, three-dimensional (3-D) groundwater flow systems around the study site and detailed hydrogeological setting should be investigated first.

著者

西沢 邦和

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.87, no.4, pp.222-226, 1978-08-25 (Released:2009-11-12)

参考文献数

7

著者

中村 高志 尾坂 兼一 CHAPAGAIN Saroj Kumar 西田 継

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.132, no.2, pp.183-196, 2023-04-25 (Released:2023-05-15)

参考文献数

47

被引用文献数

2 2

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ネパール・カトマンズ盆地における硝酸イオン(NO3−)およびアンモニウム(NH4+)による高濃度の地下水汚染について,窒素の起源とその分布の要因について調査を行なった。2009年と2010年の雨季(8月)に,丸井戸と掘り抜き井戸から計36の浅層地下水の試料を採取した結果,高濃度のNO3−(最大:63.9 mg/L)ならびにNH4+(最大:36.7 mg/L)が検出された。多くの丸井戸から採取した地下水については全溶存無機窒素に対するNO3−の含有量が多く,不飽和帯から流入するNO3−または酸素の供給により井戸内部で硝化が生じている可能性が示唆された。NO3−の窒素および酸素の安定同位体比(δ15Nとδ18O)の観測の結果,浅層地下水の主要な窒素汚染源は下水の漏水による窒素負荷であることが示された。また,NO3−濃度の減少に伴うNO3−-δ15N値の指数関数的な増加がみられたことや,δ18O値とδ15N値の間に得られる相関の近似式の傾きがおよそ0.5を示したことから,浅層地下水中において脱窒反応が生じでいることが考えられた。加えて,NO3−濃度と溶存有機炭素の間には負の相関関係がみられ,溶存有機炭素が脱窒反応の進行に強く寄与していることを示した。

著者

高波 紳太郎

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.131, no.3, pp.317-338, 2022-06-25 (Released:2022-07-08)

参考文献数

59

被引用文献数

2

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Ata welded ignimbrite (110 ka) lies beneath Ito non-welded ignimbrite and Osumi pumice fall deposit (30 ka) in the Kimotsuki Plain, southern Kyushu. Previous geomorphological studies of the Kimotsuki Plain focused on landform development after deposition of Ito ignimbrite. Landform development of Kimotsuki Plain since the last interglacial, especially until just before deposition of the Osumi pumice fall, is reconstructed using geological data collected from outcrop observations and borehole records. The basal-surface of the Osumi pumice fall deposit obtained shows that Ata welded ignimbrite had been dissected by the Kimotsuki River and its tributaries in response to the last glacial sea-level drop before the Osumi pumice fall was deposited. Longitudinal profiles along the Kushira River in 110 ka and 30 ka indicate recession of the Tanida waterfall, which formed at the edge of the Ata welded ignimbrite plateau. These profile changes imply that the Tanida waterfall retreated 2.4-6.0 km upstream between 110 ka and 30 ka. The Kushira formation, Marine oxygen Isotope Stages (MIS) 5e marine deposits under Ata welded ignimbrite, was found below the present sea-level at multiple locations in the Kimotsuki Plain. This vertical distribution of the Kushira formation indicates that the Kimotsuki Plain has been in a tectonically stable or subsidence area since the MIS 5e, in contrast with the Onejime and Natsui areas, which have been tectonically uplifting. The depositions of the two ignimbrites had significant impacts on filling the Paleo-Shibushi Bay (Sea) and the development of the Kimotsuki Plain under sea-level lowering during the last glacial period. The top-surface of basement rocks is more than −120 m below sea level at the floors of paleo valleys, even though it is adjacent to mountains composed of the basement. Further investigation of lower alluvium and its basal-surface is required for an understanding of valley incision and delta evolution of the Kimotsuki Lowland after deposition of the Ito pyroclastic flow.

著者

中井 達郎

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.116, no.2, pp.223-242, 2007-04-25 (Released:2009-11-12)

参考文献数

43

被引用文献数

4 1

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The spatial structures of a 101-103 m scale on coral reefs were understood by reading aerial photographs and investigating the topography of the fringing reef at the eastern part of Yoron Island, Ryukyu Islands. This study set a new physiographic unit (PGU) at the coral reefs as well as studied zonation. PGU has the following characteristics. (1) In an aerial photo, a linear pattern comprising micro-landform arrangements is recognized on the reef flat; (2) Seawater flowing beyond the reef crest from the open sea and entering the moat before returning to the open sea through a breakout in the reef crest or a channel flowing parallel to the shoreline constitute a very common pattern in the research area; (3) The series of currents observed in the area constitute a water system resembling a drainage water system on land and 4 systems were arranged at the eastern part of Yoron Island ; (4) The movement of seawater is controlled by landforms such as reef crests, channels and lands (a cape), which might qualify as borders of PGUs ; (5) Movements controlled by such landforms are dominant, and tend to be longer in terms of time. In this study, a physiographic unit is defined as follows. (1) A unit that is distinguishable from other adjacent areas by its geomorphological borders ; (2) And, a unit that is distinguishable from other adjacent areas when referring to the movement systems of seawater and materials.The notion of spatial structures of coral reefs of a 101-103 meter scale was substantiated by this research using the overlapping zonation approach known here as PGU on reef flats. The spatial structure makes a frame of the coral reef ecosystem. Therefore, setting a PGU is thought to be effective for application to coral reef conservation.

著者

宮縁 育夫 星住 英夫

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.126, no.5, pp.581-593, 2017-10-25 (Released:2017-11-10)

参考文献数

34

被引用文献数

2 1

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Several volcaniclastic deposits discovered at the foot of the eastern wall of Aso caldera, central Kyushu, southwestern Japan, are divided into two types: lahar deposits (Lh1-Lh5 in descending order), which contain abundant subangular to subrounded lithic clasts ( 3.5 m in diameter) set in a sandy to silty matrix, and debris avalanche deposits (DA1 and DA2), which include numerous plastically deformed fragments of tephra (ash and scoria) and soil layers in a homogenous silty to clay matrix. DA2, which underlies a paleosol dated at 5.4 ka (calibrated 14C age), is the largest volcaniclastic deposit observed in the section (more than 2.5 m thick and about 70 m wide). Because the debris avalanche deposits display no evidence that they were transported by water, they are likely to have originated from landslides triggered by intense earthquakes. Tephra chronology and 14C-dating on paleosols along the succession suggest that lahars occurred once over 900 years (6.3-5.4 ka), three times over 1400 years (5.4-4 ka), once over 400 years (4-3.6 ka) and twice (including the 2012 lahar) in the last 3600 years. This evidence indicates that the lahars occurred at an interval of 400-1800 years. In contrast, two debris avalanche deposits exist in the same succession spanning the last 6300 years. Including landslides and associated debris avalanches triggered by the 2016 Kumamoto earthquake (Mj 7.3), landslides generating debris avalanches in the Aso caldera occurred at least three times in the last 6300 years. This may suggest the frequency of large earthquakes triggering debris avalanches in the central Kyushu region, which has many active faults.

著者

水野 一晴 中村 俊夫

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.108, no.1, pp.18-30, 1999-02-25 (Released:2009-11-12)

参考文献数

47

被引用文献数

2 2

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Leopard's remains were discovered at Tyndall Glacier on Mt. Kenya in 1997. The radiocarbon dates of ca. 900 ± 100 yrs BP correspond to the shift from a warm period to a cool period and the age of the Tyndall Moraine. The leopard was probably not exposed from the ice of the Tyndall Glacier judging from the condition of the remains. The discovery of the leopard's remains in 1997 is consistent with the climatic change from a cool period which continued until the 19th century to warm period in the 20 century.The succession of alpine vegetation around Tyndall Glacier can be clarified from the conditions of glacial margins and moraines (Lewis Moraine : ca. 100 yrs BP, Tyndall Moraine : ca. 900-500 yrs BP). The Tyndall Glacier on Mt. Kenya retreated at a steady rate from the late 1950 s to 1996. The first colonist species over the new till, Senecio keniophytum, advanced at a rate similar to the retreat of the glacier. The species growing near the ice-front of Tyndall Glacier colonized in tandem with the retreat of the glacier. Till age and stability of land surface are important environmental factors controlling the vegetation pattern around Tyndall Glacier. The pioneer species make humus which results in an improved soil condition. About 70 to 100 yrs elapse from the glacial release before such large woody plants as Senecio keniodendron and Lobelia telekii grow on the glacier foreland.

著者

木内 信蔵

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.69, no.3, pp.119-125, 1960-07-30 (Released:2009-11-12)

参考文献数

9

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Professor Hartshorne's 'The Nature of Geography ' has been widely read among Japanese professional geographers, since Professor I. Matsui had reviewed and then Dr. S. Nomura had translated it into Japanese. Its contribution was too much to write here, but he felt it necessary to supply deeper considerations.The writer generally agrees with the “Perspective” view and would like to express his concept here. Geography is a highly synthesized science, and its study is based on the active regions which have been formed through times and with intimately related human and physical phenomena. But complete synthesis is almost impossible. It should be strived for, with analyzing, comparing actual regions assisted by topical studies.But there remains several questions, for instance valuation of Fr. Ratzel's work with relation to prerent ecological study. And how we could get a proper seat of geography, as chorological science, among traditionaly divied natural and human or social sciences ?

著者

松田 亀三

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.88, no.4, pp.230-245, 1979-08-25 (Released:2009-11-12)

参考文献数

107

被引用文献数

14

著者

宮崎 真由美 石村 大輔

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.6, pp.735-757, 2018-12-25 (Released:2019-01-30)

参考文献数

37

被引用文献数

5 6

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Marine terraces on the northern Sanriku Coast are mapped, verifying their emergent times with a tephra analysis to provide accurate information on long-term coastal uplift along the Sanriku Coast. The results contradict the conventional view of century-long subsidence and coseismic subsidence associated with the 2011 Tohoku-oki earthquake. Eight visible tephra layers are found to cover the Taneichi surfaces reported as Marine Isotope Stage (MIS) 5 marine terraces in previous research on the northern Sanriku Coast, and these correlate with To-H, To-Of, To-G, To-Ok2, To-AP, To-CP, Toya, and ZP2 tephra layers previously identified at the Kamikita Plain based on petrographic properties. Consequently, because the Toya tephra (ca. 112-115 ka) covers marine sand and/or gravel beds composing the terraces, they are confirmed to be MIS 5e marine terraces. The paleo-shoreline of the MIS 5e marine terraces is inferred, considering topographic profiles and aeolian deposits covering terrace surfaces, and their heights are measured with high-resolution digital elevation models to be ca. 40 m above the present sea level at the Kamikita Plain and ca. 20-30 m at the northern Sanriku Coast. In addition, uplift rates from the Kamikita Plain to the northern Sanriku Coast are estimated to be 0.3 mm/yr and 0.1-0.2 mm/yr, respectively, tending to gradually decrease toward the south, and may be subject to subsidence further south along the southern Sanriku Coast.

著者

高橋 誠 松多 信尚

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.2, pp.193-209, 2015-04-25 (Released:2015-05-14)

参考文献数

18

被引用文献数

6 5

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Generally, the impacts of a tsunami can be understood in terms of the corresponding relationships between hazard scale and extent of building damage and loss of human life. Focusing on community-scale statistics of the municipalities of Kamaishi, Kesen'numa, Minami-sanriku, and Yamamoto, which were severely affected by the 2011 Tohoku Earthquake, significant variations are observed in the mortality rates at affected villages that experienced the same levels of building damage. Moreover, differences in the geographical locations of the villages also impact their mortality rates. A village with a high mortality rate is situated either on a coastal plain or on an inland valley plain some distance from the sea, whereas a village with a low mortality rate is paradoxically in close proximity to the sea, often facing a small bay. Close interrelationships are identified among geographical conditions and possible evacuation activities, which relate to the geographical imaginations of inhabitants based on their inherent local knowledge and interactions with physical and built environments. Interviews with survivors indicate decisions to escape could not be made quickly after the earthquake occurred. Rather, people were confused regarding the occurrence and magnitude of the tsunami and the provision of evacuation sites. The tsunami waves were often different from those that were formally forecast and broadcast, which compelled people to act flexibly. Consequently, it is argued that it is necessary to emphasize the effects of local geographies on interactions between tsunami waves and evacuation activities from a grassroots perspective when preparing for future tsunamis.

著者

益田 晴恵

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.132, no.1, pp.1-16, 2023-02-25 (Released:2023-03-09)

参考文献数

53

被引用文献数

3

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Occurrences of non-volcanic hot and mineral spring waters, found in Niigata and the surrounding areas, as well as central to southern Kinki District, are documented in relation to the local tectonics to discuss on the importance of plate tectonics as sources of heat and dissolved chemical compositions in the deep groundwater/fluid cycle. Fossil seawater was altered at different temperatures, and remains as low-temperature mineral waters in Gunma Prefecture, and as oil and gas field brine and related hot springs in Niigata Prefecture and surrounding areas. One of the hot springs in Niigata, i.e., Matsunoyama Hot Spring, is known to contain geo-pressure hydrothermal water. The brines in Niigata Prefecture are heated via tectonics at the boundary between the Eurasian and North-American plates without contaminating modern local meteoric water. In the Kinki District, hot spring waters > 40°C appear only in three regions: coastal area along the Sea of Japan, Arima and surrounding area of Osaka Basin, and southern part of Kii Peninsula. In this area, mantle-derived fluids, such as He and CO2, are upwelling with slab-derived saline waters from the subducting Philippine Sea Plate. Non-volcanic hot spring waters occasionally give the important information on heat and energy cycles at the plate boundaries, as well as valuable information for understanding the mechanisms of inland earthquakes related to the deep-fluid movements.

著者

茂木 昭夫

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.79, no.5, pp.243-265, 1970-10-25 (Released:2009-11-12)

参考文献数

47

被引用文献数

6 6

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The Philippine Sea is bounded on the west by the southern half of Japan, the Ryukyu Islands and the Philippines, and on the east by the arcuate seafloor ridge extending from Japan to the Palau Islands through the Mariana Islands. Both arcuate structures are associated with deep sea trench, island arcs, volcanic activity, deep focus earthquakes and negative gravity anomalies. This abyssal deep basin which consists of the oceanic crust is separated into the east and the west basin by the Kyushu-Palau Ridge. The east basin is somewhat shoaler, and can be divided by the central narrow zone at 23°N into two parts, Shikoku Basin and West Mariana Basin, which gradually rise toward the Honshu-Mariana Ridge. There are, however, several seamounts, called the Kinan Seamount Chain, arranged in NNW-SSE direction in the Shikoku Basin. And on its southern extension, there are several troughs, called the West Mariana Trough, arranged is N-S direction. The Shikoku Basin is composed of the smooth floor of the northeastern part and the mountainous area of the southwestern part. The West Mariana Basin is also divided into the abyssal plain on the east and abyssal hill region on the west. And the West Mariana Trough is running on its boundary.The west basin, Philippine Basin, is unusually deep. A region of rugged topography which can be termed the Daito Ridges lies at the northernmost part of the basin. These several parallel ridges elongate from the respective coral islands to southeastward intervening narrow depressions. There are flat plains at the depth of about 1500, 2000 and 3000 m on the northern side of each of the ridges. There is the striking feature, called Central Basin Fault, in the central part of the Philippine Basin. Central Basin Fault which is the low ridge associated with trough in the NW-SE direction separate the Philippine Basin into the north basin and the south basin. On the Philippine Basin floor, the most extensive area is abyssal hill region. Abyssal plains are developed only in limited localities such as the west side of the northern arc of the Kyushu-Palau Ridge.From the description on the submarine topography of the Philippine Sea the author concluded as follows.(1) A few ridges and seamounts not associated with trench are running parallel to the Ryukyu-Philippine Arc and Izu-Mariana Arc : one Kyushu-Palau Ridge, two Kinan Seamount Chain-West Mariana Trough, three Nishi-Shichito Ridge-West Mariana Ridge. These ridges close the space eastward. And basements of basins which intervened between each ridges rise toward the east.(2) There are another ridges having unusual trend. The Daito Ridges have E-W trend and the minor ridges on the Izu Ridge have the NE-SW trend.The numerous minor ridges which construct the abyssal hill region also have the E-W trend on the northern part of the Philippine Sea, although its trend changes to the N-S trend southward gradually. These trends are correspond to the Southwest Japan Arc.(3) Ridges with E-W trend are cut by the ridges with N-S trend, alike the Japan Arc crossed by the Izu-Mariana arc.(4) Kyushu-Palau Ridge consists of two arcs, northern arc parallel to the Ryukyu Arc and southern arc parallel to the Philippine Arc. These two arcs are separated by the Central Basin Fault. Another possible fault runs from the depression in the east side of the northern Kyushu-Palau Ridge to the junction of the Izu-Ogasawara Arc and the Mariana Arc. The southern arc (Mariana) remarkably projects to the southeast along this fault.(5) Abyssal hill provinces in the Philippine Sea occupy the western half of each basins usually. Some of the flat plains occupying the eastern half appear to the archipelagic apron which is constructed by the eruption on the concave side flank of the arcuate ridges.

著者

鈴木 弘道

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.103, no.5, pp.595-596, 1994-10-25 (Released:2009-11-12)

参考文献数

1

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.8, no.8, pp.432a, 1896-08-10 (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.9, no.7, pp.333a-334, 1897-07-15 (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.19, no.9, pp.695, 1907-09-15 (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.1, no.6, pp.264, 1889-06-25 (Released:2010-12-22)