著者

新井 健司

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.105, no.4, pp.485-491, 1996-08-25 (Released:2009-11-12)

参考文献数

9

著者

岩塚 守公

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.80, no.1, pp.63-64, 1971-02-25 (Released:2009-11-12)

著者

尾鼻 浩一郎 藤江 剛

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.2, pp.113-123, 2017-04-25 (Released:2017-06-12)

参考文献数

34

被引用文献数

2 2

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An important site of hydration and alteration of the incoming oceanic plate prior to subduction, the trench-outer rise region determines the distribution and amount of water transported into the Earth's mantle by subduction of the oceanic plate. Recent seismic surveys conducted in the northwest Pacific Ocean indicate reductions of seismic velocities within the oceanic crust and the uppermost mantle of the incoming Pacific plate toward the trench. These velocity reductions probably reflect hydration and alteration of the Pacific plate prior to subduction, although there are regional variations in the crustal structures of the oceanic lithosphere. Besides structural change, the stress regime within the incoming Pacific plate, which is derived from seismicity observations in the trench-outer rise region of the Japan Trench after the 2011 Tohoku-Oki earthquake, suggests that extensional stress of the incoming Pacific plate extends down to a depth of about 40 km. However, normal-faulting earthquake activity within the incoming Pacific plate was limited at depths shallower than about 20 km before the 2011 Tohoku-Oki earthquake. The change of the depth extent of normal-faulting earthquake activity suggests that the 2011 Tohoku-Oki earthquake changed the stress regime within the incoming Pacific plate. Distribution and focal mechanisms of shallow seismicity within the oceanic crust indicate that seismicity is affected by the pre-existing structure, which probably formed at the mid-ocean ridges. Heterogeneity and pre-existing structure of the incoming oceanic lithosphere should be taken into account when considering hydration and alteration of the oceanic lithosphere subducting into the trench.

著者

大場 忠道

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.115, no.5, pp.652-660, 2006-12-25 (Released:2009-11-12)

参考文献数

11

被引用文献数

4 8

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Five distinct paleoenvironmental changes in the Japan Sea over the last 95 ka are revealedfrom the oxygen and carbon isotopes of foraminiferal tests in a piston core recovered from the Oki Ridge. Between 95 and 27 ka, the warm Tsushima Current did not flow into the Japan Sea.The environment at the seafloor fluctuated between anoxic to weakly oxic conditions. Between 27and 17 ka, freshwater input to the Japan Sea, probably from the surrounding land, stratified the water column, and the resulting severe anoxic conditions eliminated most benthic fauna. Between 17 and 10 ka, the cold Oyashio Current flowed into the Japan Sea through the Tsugaru Strait, reestablishing deepwater ventilation. Between 10 and 8 ka, bottom conditions changed from anoxic to oxic. At 10 ka, the warm Tsushima Current started to flow into the Japan Seathrough the Tsushima Strait, establishing the modern oceanographic regime at 8 ka.From high-resolution oxygen and carbon isotope analysis of both benthic and planktonic foraminifera from an IMAGES core collected from off Kashima, central Japan, very large (20°C) sea surface temperature (SST) fluctuations can be reconstructed for the last 150 kyr, with minimum SSTs of 3-4°C during Marine Isotope Stage (MIS) 2 and MIS 6/5e transition, and with peak SSTs of 22-23°C during early MIS 1 and MIS 5a/4, 5c/5b, and 5e/5d transitions. The SSTs varied in parallel with changing carbon isotope differences between Globorotalia inflata and Globigerina bulloides, which suggests that the SST changes were primarily caused by latitudinal displacements of the Kuroshio-Oyashio Currents. A strong correlation between the SST shifts and orbital forcing indicates that latitudinal displacements of the Kuroshio-Oyashio Currents were influenced by summer insolation at 65°N.

著者

藤井 敏嗣

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.97, no.3, pp.209-213, 1988-06-25 (Released:2009-11-12)

参考文献数

22

著者

村田 明広

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.104, no.1, pp.82-93, 1995-02-25 (Released:2010-11-18)

参考文献数

24

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The Paleogene Hyuga Group of the Aradani Area in East Kyushu is regarded as an accretionary complex in the Shimanto Terrane. The Group was formerly inferred to form a melange including various sized blocks of sandstones, red and green siliceous mudstones, and basaltic volcanic rocks. The siliceous mudstones are not blocks in the melange, but occur as a low-angled thrust sheet of 40m thick.The Hyuga Group of the Aradani Area consists of four tectonic units;(1) lower chaotic unit, (2) siliceous mudstone unit, (3) mudstone unit, and (4) upper chaotic unit in ascending order. Each unit except for the siliceous mudstone unit forms a duplex structure, in which strata are imbricated, dipping 30° to 50° Each duplex is formed by mono-lithologic strata. The fundamental structure of the Paleogene Shimanto Terrane in Kyushu is characterized by low-angled nappe structures with stacked duplexes, in which duplexes lie one above the other, similarly to those of the Cretaceous Uchinohae Formation in South Kyushu.Original succession of the Hyuga Group is (1) basaltic volcanic rocks, (2) red and green siliceous mudstones of Middle Eocene, (3) black mudstones of Late Eocene, (4) sandstones and alternating beds of sandstone and mudstone of Late Eocene to Early Oligocene. Chaotic beds of melange facies originate from all above-mentioned strata. The siliceous mudstones, which are considered to be hemipelagic sediments, were subducted, and then formed a thrust sheet during underplating. The siliceous mudstones were probably situated in the decollement horizon, but did not flow as a lubricant layer.

著者

歌代 慎吉 岩淵 義郎

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.80, no.2, pp.77-88, 1971-04-25 (Released:2009-11-12)

参考文献数

8

---

Sagami Bay is structurally active area through the geological history, and also the epicenter of the Great Kanto Earthquake (1923) was here. To make clear the features of the topography and geological structure of the active area, it seems to be fundamental step for the earthquake predication today.In April to May 1968, the surveying ship Meiyo of the Japanese Hydrographic Office carried out the sea bottom surveys of Sagami Bay with echo-sounder, seismic profiler and proton-geomagnetometer, including the dredge and coring operation, and took the data from about 3000 kilometers of her traverses.The ship's position was mainly determined by an auto-tape system with the estimated accuracy of ±2 meters. The simultaneous measurement of magnetic intensity, bathymetry and submarine geological structure by air-gun system allows direct comparison of the measurements. Figure 1 is the track chart of the Meiyo and figures 2 and 3 are some profiles based on the collected data.From the analyses of the collected data mentioned above, the topography and geological structure and magnetic anomaly of Sagami Bay can be summarized as follows.1. TopographyFigure 4 shows the bathymetric chart of Sagami Bay. In the eastern part of the bay, many banks and small basins range from NW to SE. Many submarine canyons cross the topography mentioned above and incise deeply, so that especially small basins do not keep their complete shape.The central part of the bay is called Sagami Trough, which is deeper than 1 kilometer. The floor of the trough generally shows low relief with the exception of the eastern part of the trough, which submarine canyons flow into, and gentle slope with the trend of NS at the central part, facing east and reflecting the fault topographically.In the western part of the bay, continental shelf and slope are monotonous, comparing with its eastern part. There are several conical banks between the Izu Peninsula and O Shima Island.2. Geological structureGeological structure based on the seismic profiler is shown in Figure 5. The area surrounded Sagami Bay is relatively uplifted zone in contrast with the trough showing the relative subsidence. Acoustic basement rock outcrops on the uplifted zone and may probably be composed of the Hayama group (Lower Miocene) and partly the lower part of the Miura group (Middle Miocene).The large part of the thinly layered sediment at the upper part of sediment body in Sagami Trough is younger than the age of uplifted zone mentioned above. The layered sediment is wholly tilted to the axis of the trough, and is found the folding in the margin of the trough and also the active fault near surface. Its maximum thickness is found at the northern part of the trough, and is over about 1 second in the reflection time approximately.The area along the Izu Peninsula and around O Shima Island is extensively covered with the volcanic products. Small banks between the Izu Peninsula and O Shima Island are volcanic cones of the effusive body which pierced through the layers probably composed of the Shirahama group (Middle to Upper Miocene).3. GeomagnetismThe resultant magnetic chart, contoured at intervals of 100 gammas, was in Figure 6. The results of the magnetic surveys revealed that there were many magnetic anomalies of about 500 to 800 gammas off shore along the Izu Peninsula in Sagami Bay and a pair of remarkable positive and negative magnetic anomalies of about 1800 gammas in the sea area along the west side of O Shima Island.On the other hand, it was found that there was no remarkable magnetic anomaly in the central part and eastern part of Sagami Bay.From the results of magnetic surveys and submarine geological structure, it can be concluded that the sea area off shore along the Izu Peninsula and around O Shima Island are composed of volcanic rocks of higher magnetic susceptibility, such as basalt or andesite.

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.7, no.10, pp.567a, 1895-10-10 (Released:2010-12-22)

著者

吉岡 真弓

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.123, no.4, pp.472-485, 2014-08-25 (Released:2014-09-01)

参考文献数

42

被引用文献数

2

---

Besides the immediate need for alternative sources of energy, it has become increasingly crucial to maximize the use of the limited energy sources that remain after the Great East Japan Earthquake. Tokyo, which consumes an enormous amount of energy, should lead this effort by exploring ways of becoming an advanced energy-saving city in the future. This paper focuses on the thermal energy of water, which is one of the available energy sources in Tokyo. The potential of the thermal energy of water could be harnessed to improve the thermal environment and reduce energy use in Tokyo. One way to use this energy is to harness the heat of evaporation by sprinkling water on a pavement in order to improve the thermal environment in summer in cities where the heat island phenomenon is observed. This technique of sprinkling water is known to the Japanese as Uchimizu, and it is a time-honored custom in Japan. Some studies involving field experiments and numerical simulation have investigated the cooling effect of sprinkling water scientifically by applying systematic sprinkling as a countermeasure for the formation of heat islands. The other way of employing this source of energy is to use a ground-source heat pump system, which is a high-performance cooling and heating system, using subsurface and groundwater thermal energy efficiently. Active use of thermal energy of water is considered to be one strategy that Tokyo can adopt to become an energy-saving and environmentally friendly city in the future.

著者

赤坂 郁美 安藤 晴夫 横山 仁 大久保 さゆり 高橋 一之 泉 岳樹 三上 岳彦

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.120, no.2, pp.309-316, 2011-04-25 (Released:2011-06-30)

参考文献数

11

被引用文献数

5 7

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To investigate the spatial and temporal variability of the urban heat island, a high-spatial density meteorological observation system was set up in the Tokyo ward area by Tokyo Metropolitan Research Institute for Environmental Protection (TMRIEP) and Tokyo Metropolitan University from July 2002 to March 2005. The observation system was named Meteorological Environmental Temperature and Rainfall Observation System (METROS) and consisted of two observation networks named METROS20 and METROS100; METROS20 was made to observe meteorological factors (wind direction and speed, pressure, rainfall etc.) on the roofs of 20 buildings; METROS100 was made to observe temperature and humidity in instruments screens of 106 elementary schools. Since April 2005, observations of temperature and humidity were continued with the instruments screens of elementary schools by TMRIEP. This observation network was maintained until March 2010. Based on their observations, temporal and spatial characteristics of thermal environment of Tokyo have been investigated such as temperature range, especially in summer. For example, warmer areas differ between daytime and nighttime as shown by spatial patterns in rate of time exceeding 30 degrees Celsius and number of sultry nights: the warmer area is located from central part to northern part of the Tokyo ward area during daytime and from central part to coastal area during nighttime.

著者

坂井 尚登 三浦 一彦 中西 清

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.103, no.1, pp.64-67, 1994-02-25 (Released:2010-10-13)

参考文献数

6

著者

尾方 隆幸

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.1, pp.v, 2015-02-25 (Released:2015-03-11)

参考文献数

1

著者

藁谷 哲也

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.4, pp.455-471, 2017-08-20 (Released:2017-09-27)

参考文献数

88

被引用文献数

4

---

It is difficult to estimate weathering rates of rocks based on actual landforms. However, using stone-built architectures, artifacts, and traces of human activity on rock surfaces, weathering rates of rocks under weathering-limited conditions can be obtained easily because stone-built heritages, in general, have a geometrical shape and zero-datum levels. In addition, it is possible to estimate weathering rates of a millennium-scale and changes of rates up to a millennium scale. Many studies on weathering rates of rocks use stone-built heritages. This study reviews recent geomorphological studies that estimate weathering rates, and summarizes their trends. Most of the studies analyze gravestones and churches built since the 19th and 11th centuries, respectively. Such stone-built heritages are more commonly located in humid temperate areas. Weathering rates are estimated mainly from surface recession or surface loss of gravestones and church-building stones. The major three building stones—carbonate rocks (rate: 2-90 mm/ka), sandstone (8-100 mm/ka), and granite (5-65 mm/ka)—have different ranges of weathering rates. Among these stones, the rates for carbonate rocks are sensitive to climatic conditions and atmospheric sulfur dioxide concentrations. The results of the studies reveal that weathering rates show an obvious dependence on aspects. North-facing surfaces tend to have lower rates than surfaces facing other cardinal directions because each surface has different temperature and moisture conditions due to insolation. Moreover, the studies reveal that temporal changes in weathering rates rarely fit a simple linear model. Changes in atmospheric acidity, landform development, and vegetation cover rapidly affect the intensity of weathering processes and cause fluctuations in weathering rates.

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.120, no.2, pp.Cover02_1-Cover02_2, 2011

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2010年は太平洋高気圧におおわれて8月を中心に暑さが厳しく,6月以降,東京でも最高気温が35℃を超える猛暑日が13日間,明け方の気温が25℃以下に下がらない熱帯夜の日数が56日間という記録的な高温状態が継続した.<br> 表紙写真は,都心部で最高気温が36.5℃を記録した8月15日の正午頃に,都心湾岸部の上空約5000フィート(1525m)からヘリコプターに搭載したサーモグラフィーで捉えた地表面の熱画像(放射輝度温度分布)である.なお,放射率は一律(ε=1.0)に設定し,表面材質の違いによる補正は行っていない.<br> 皇居(A)や浜離宮庭園(E)など,緑豊かなエリアが比較的低温を示すほか,南北に流れる隅田川(F)の水面が28℃以下と低くなっており,東京湾からの涼しい海風を通す「風の道」としても有効に働いていることがわかる.また,東京駅周辺(B)や汐留の高層ビル群(C)付近も比較的低温になっている.<br> 一方,湾岸の埋め立て地域や隅田川東岸に広がる密集した中低層商工業地帯の表面温度は40℃を超えている.築地の東京都中央卸売市場(D)の表面温度が高いのは,建物の屋根面の材質が影響していると考えられる.<br>(文:三上岳彦 熱画像:スカイマップ株式会社)

著者

平田 大二 山下 浩之 坂本 泉 小田原 啓 滝野 義幸 鬼頭 毅 藤巻 三樹雄 萬年 一剛 新井田 秀一 笠間 友博 齊藤 靖二

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.911-916, 2010-10-25 (Released:2011-01-21)

参考文献数

12

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The bottom topography of lake Ashi-no-ko, in the Hakone volcano caldera, was examined using the SeaBat8101 narrow multi-beam sonar system. The purpose of micro-topographical observations of the lake bottom is to understand the tectonic relations between the historical formation-process of the caldera and the strike-slip motion in the Tanna-Hirayama active fault system. At the southeastern part of the lake, west of the Dougashima, undulations at the bottom such as swells, hollows, and stairs extending in the northwest-southeast direction, were observed. These bottom-forms show a northern extension of the Hakonemachi active fault, running along the east side of lake Ashi-no-ko. They may correspond to one of the north spray faults of the Kita-Izu active fault system, which is the source of the A.D.1930 Kita-Izu earthquake, and to motions of the western margin of the Manazuru micro-plate, in relation to caldera formation as a strike-slip basin.

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.88, no.4, pp.264-271, 1979-08-25 (Released:2009-11-12)

参考文献数

26

著者

福井 一喜

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.595-615, 2017-10-25 (Released:2017-11-10)

参考文献数

42

被引用文献数

4

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The transformation of Kusatsu Onsen spa resort in Gunma prefecture, at the margins of the Tokyo metropolitan area, is elucidated. The use of the Internet by the accommodation industry is analyzed based on the dependence of the area on travel agencies in both information distribution and supply and demand phases. These specifically identify the possibilities and limits of region-led tourism development. The results are as follows. Many accommodations at Kusatsu Onsen independently use travel agencies in the information distribution phase. On the other hand, in the supply and demand phase, both dependence on and independence from travel agencies are confirmed. Through the use of the Internet in the accommodations, the possibility of promoting region-led tourism development at Kusatsu Onsen is increasing as a whole in the information distribution phase. This possibility in the supply and demand phase is due more than ever to the management conditions and management abilities of the each accommodation. Using the Internet as an opportunity, each accommodation tries to overcome the disadvantages of its management conditions and create tourism services. Individual tourists with diverse and advanced tourism demand gather at spa resorts at the margins of the Tokyo metropolitan area. The area responds to tourism demand in the Tokyo metropolitan area, given changing relations of dependence between travel agencies and the areas they serve against the backdrop of the development of personal travel and information socialization. On the other hand, local organizations are attempting to form the functions of travel agencies; however, they are not succeeding. Accommodation owners call for organizations to act as the cores of local networks to promote the management and marketing activities of each accommodation. As described above, at Kusatsu Onsen, a situation is created for continuously providing non-daily life services to the tourism market in the Tokyo metropolitan area, and local accommodations and organizations produce tourism resources independently. In the information distribution phase, the accommodations and local organizations form an environment where each can effectively communicate its own attractions, and the possibility of region-led tourism development is widely acknowledged. On the other hand, in the supply and demand phase, such a possibility can be somewhat recognized. Some accommodations have a trend of great dependence rather than a tendency of becoming independent of travel agencies, and it is also difficult for local organizations to play the roles of a travel agency. These factors suggest the limits of region-led tourism development.

著者

小島 茂明 渡部 裕美 藤倉 克則

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.6, pp.1174-1185, 2009-12-25 (Released:2010-03-23)

参考文献数

64

被引用文献数

2 1

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In deep-sea reducing environments, such as hydrothermal vent fields and cold seep areas, biological communities with huge biomass are often observed. Such communities associated with bacterial chemosynthesis, which are composed of species endemic to these environments, are founded with hydrothermal activities and succeed with changes of activities. Over a longer timescale, genetic deviations among local populations and speciation occur during the course of a series of activities and finally new faunal groups diverged. We attempt to estimate the ages of various hydrothermal phenomena on various timescales from 10 to 107 years on the basis of the evolutionary ecology of animals endemic to hydrothermal vents as part of the “Taiga project”. In this paper, we introduce communities in hydrothermal vent fields and describe the principals of methodologies for age estimation, which we are now planning, and the expected results.

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.12, no.3, pp.188a-189, 1900

著者

鈴木 ドロータ 高木 秀雄 河本 和朗 中村 祐治 中村 れいら

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.4, pp.587-605, 2015

被引用文献数

1

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本州弧に対する伊豆–ボニン弧への中新世の衝突の影響を受けて,中央構造線の東西走向が,紀伊半島東部伊勢地域で東方に向かって東北東–西南西へと曲がりはじめるものとされている。しかしながら,伊勢地域では第四系堆積物が広く覆っており,都市化も進んでいることから,中央構造線の地表トレースの正確な位置は不明瞭である。中央構造線の位置の正確な把握は,たとえば地盤の違いを反映した地震動予測に資することや,中部日本における中央構造線の折れ曲がりのより正確な説明を与える上でも重要である。本論は伊勢地域(玉城町・伊勢市)に存在する(1)美和ロック玉城工場,(2)伊勢市役所,(3)伊勢観光文化会館のボーリングコアの岩石学的検討を行うとともに,伊勢市内のその他の建設基盤調査資料や,玉城町大池の断層岩類,領家帯に分布すると考えられる宮川沿いの中新統礫岩,伊勢市内に存在する三波川結晶片岩の露頭など,限られた露頭の地質調査結果から,中央構造線の位置をより正確に求めることができた。今回の調査で,三波川変成岩が一部に露出している伊勢神宮外宮に存在する中央構造線が正宮付近に想定され,ジオツーリズムとリンクしたその教育的活用が望まれる。