著者
中埜 貴元 小荒井 衛 宇根 寛
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.259-271, 2015-04-25 (Released:2015-05-14)
参考文献数
23
被引用文献数
5 8

Landform classification data are useful for assessing land liquefaction. Koarai et al. (2013) suggested a comprehensive risk assessment table for land liquefaction by combining 7.5-arc-second Japan engineering geomorphologic classification data (Wakamatsu and Matsuoka, 2009) with seismic intensity. The Geospatial Information Authority of Japan (2007) suggested a risk assessment standard for land liquefaction using land condition data produced by the Geospatial Information Authority of Japan. Our new hazard assessment standard for land liquefaction is based on land condition data and a risk assessment table produced by Koarai et al. (2013). Furthermore, a landform classification and hazard assessment standard of land liquefaction is suggested to create a simple land liquefaction hazard map. This information allows land liquefaction hazard to be assessed from land condition data or 7.5-arc-second Japan engineering geomorphologic classification data and to interconvert both land liquefaction hazard assessments.
著者
財城 真寿美 三上 岳彦 平野 淳平 Michael GROSSMAN 久保田 尚之 塚原 東吾
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.4, pp.447-455, 2018-08-25 (Released:2018-10-05)
参考文献数
14
被引用文献数
4

Past meteorological records are important for improving our understanding of past, present, and future climates. Imaging and digitization of historical paper-based instrumental meteorological records must be carried out before these records are lost to decay. This kind of activity called “data rescue” is now taking place at many institutions around the world. A data rescue project is underway to preserve Japanese instrumental meteorological records from the 19th century. These data were collected by foreign residents and visitors, Japanese scientists influenced by Dutch science, and by Japanese merchants. Recently, meteorological measurements taken at Mito from 1852 to 1868, and at Yokohama in 1872 and 1873 have been found. Based on instrumental records collected through this data rescue project, a warmer climate in the 1840s and 1850s around the South-eastern Kanto Region has been identified. Large year-to-year variations of winter temperatures have also been detected.

1 0 0 0 OA 地名の話

著者
柳田 國男
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.24, no.10, pp.673-682, 1912-10-15 (Released:2010-10-13)
著者
海津 優
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.129, no.2, pp.275-283, 2020-04-25 (Released:2020-05-12)
参考文献数
11
被引用文献数
4

In 1880, Inoh Tadataka surveyed the meridian arc length corresponding to one degree of latitude difference. A record of calculations is contained in a handwritten manuscript titled “Sokuchidosetsu” or “On Meridian Arc Length Corresponding to One Degree.” The uncertainty of latitude for a short arc is dominant and is estimated to be about 0.42 minutes. This uncertainty is in accord with the rounding latitude at half a minute in many documents that refer to Inoh's work on coordinates. Some points were used for astronomical observations of latitude in two successive years. A comparison of those results suggests some bias in the results and a standard deviation around the mean of about 1.3 minutes. This is obviously much more than the uncertainty estimated from the scatter of one degree meridian arc length against the N–S component of a great circle connecting the ends of a route. Data sets of astronomical latitude observations surveyed independently help clarify the uncertainty associated with Inoh's latitude observations obtained from field surveys. The scatter of distance and latitude difference data around the linear trend suggests that the uncertainty of the N–S distance is about 7.3/10,000.
著者
鈴木 純子
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.129, no.2, pp.161-179, 2020-04-25 (Released:2020-05-12)
参考文献数
28
被引用文献数
3

The accomplishments of the survey projects of Inoh Tadataka in early 19th century Japan should not be evaluated merely from the visible results of his maps of the country. The latest surveying technologies and instruments, as well as his knowledge of the astronomical almanac, had a wide range of influences upon the surveying skills and astronomical knowledge of local surveyors and scholars. Inoh's Sokuryo-nikki (Survey diary) and records of local counterparts preserved in throughout Japan are reviewed and connections are evaluated. The records have been unearthed in recent years by historians editing regional histories and local history researchers. These investigations are important aspects of recent studies of Inoh's projects and supplement basic research of Otani (1917) and Hoyanagi (1974). During his journeys to survey Japan over seventeen years, Inoh kept a daily journal. It records some 12,000 people who attended or guided Inoh's team. However, his journal lacks details of connections among them. Local records contain extensive practical information concerning the project. Generally, officials of local lords or village officials accompanied the team of surveyors. They would learn on the job. According to their records and letters, some made and improved upon Inoh's surveying instruments. Others wanted to become students of Inoh and later attended private classes in Edo. Still others discussed calendrical calculations, trigonometric functions, and logarithm. Subsequently, some returned to their home regions and took charge of local surveys. As a result, we can recognize the wide range of influences the surveying project of Inoh Tadataka had.
著者
吉田 樹
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.2, pp.233-248, 2014-04-25 (Released:2014-05-16)
参考文献数
20
被引用文献数
4 4

This paper describes the history of regional and transport planning in the Tokyo Metropolitan Area, and considers the relationship between urban structure and transport planning. The network of major roads in Tokyo has been shaped by revitalization planning since the Great Kanto Earthquake of 1923 and the Pacific War. However, because of financial difficulties, some roads in the urban plan remain incomplete to this day. On the other hand, the Metropolitan Expressway network was planned around 1950, and about 940 thousand vehicles use the expressway every day. The railway companies around Tokyo, notably Japan National Railways, faced problems of overcrowding because the population of the Tokyo Metropolitan Area had increased and suburbs were created during the high economic growth period from the mid-1950s. Japan National Railways and Council for Transport Policy planned construction of new lines and the congestion rate of railways tended to decrease. Urban structure planning of Tokyo Metropolitan aimed to have a multipolar pattern during the tenures of former Tokyo Governors Shun-ichi SUZUKI and Yukio AOSHIMA. However, around a year after taking office, the former Tokyo Governor, Shintaro ISHIHARA, suggested the concept of a “ringed megalopolis,” which is invested in central Tokyo including subcenters for improving international competitiveness. Even with the different strategy for reconstructing an urban structure, road and railway planning has not changed. Transport planning in Tokyo metropolitan area has depended on urban planning that is designed not to interfere with the placement of urban functions, but follows and satisfies demand resulting from suburbanization. However, because an urban structure with a compact city has become more important, urban structure planning is required to be coordinated with transport planning.
著者
M. SANTOSH 千秋 博紀
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.1, pp.100-114, 2011-02-25 (Released:2011-05-20)
参考文献数
50
被引用文献数
3 10

The history of supercontinents is briefly reviewed in relation to the origin of the Japanese Islands. The Japanese Islands formed part of the S. China Block, which was a part of supercontinent Rodinia at 1.0 Ga. Rodinia was rifted at 600 Ma, separating S. China Block, N. America, Australia and other continents, to generate the Proto-Pacific Ocean in between. On the other hand, the Hida and Oki islands belong to the N. China Block, which has much longer history than the S. China Block, extending back to 1.9-2.0 Ga with minor older rocks dating back to 3.8 Ga. The 1.8-2.0 Ga high-grade gneiss in the Hida and Oki belts may be part of the 1.8-1.9 Ga Nuna/Columbia supercontinent within which N. China-Japan occurred at the NE corner, as judged from key parallel belts of 1.8-1.9 Ga in N. China. The position of Japan at 1.0 Ga within Rodinia was at the center together with S. China and western margin of N. China. The oldest fossiliferous rocks in Japan may extend back to the Early Cambrian to Ediacaran formed during the rifting of Rodinia directly after Neoproterozoic snowball Earth. Initiation of subduction began ca. 520 Ma, and evolved through five Pacific-type orogenies along the southern margin of S. China. On the other hand, the Hida and Oki belts suffered the Triassic collision orogeny at 230-240 Ma, involving platform sediments up to the Carboniferous age. The final tectonic emplacement above the Jurassic accretionary complex may be related to the extensional event during the opening of the Japan Sea in the Miocene.
著者
兼岡 一郎
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.668-673, 2008-06-25 (Released:2010-05-14)
参考文献数
10

Based on radiogenic isotopes, we can obtain information about the Earth related to time. Radiometric dating is a typical example. Due to the advanced development of current analytical techniques, radiometric ages covering the Earth's entire history can be obtained with an error of less than 1%, even for a mineral crystal. However, there still remain problems to be clarified including the reliability of decay constants and the meanings of value obtained. In another approach, an isotope ratio including a radiogenic isotope can be used to clarify the evolution of the Earth. By applying multiple isotope systematics for typical volcanic rocks such as Mid-oceanic ridge basalts (MORBs) and oceanic island basalts (OIBs), we conjecture the chemical state of the Earth's interior such as the degree of chemical fractionation and degassing. As an additional material used for clarifying the Earth's deep interior, I demonstrate the significance of kimberlites which might reflect the state of the Earth's deep interior more directly than OIBs.
著者
岡部 篤行
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.2, pp.312-323, 2008-04-25 (Released:2010-06-02)
参考文献数
33
被引用文献数
3 3

This paper reports the history of GIS developments in the 1970s and 1980s in Japan. The paper outlines ten GIS development projects: Small Area Information Systems, UIS-I, Geographic Information Processing System and Overlay Mapping Technique, Computer Graphic Systems for City Planning, ISLAND, TUMSY, Local Government GIS, Geographical Information Processing, TOGIS, and UIS-II.
著者
梶田 真
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.1, pp.53-72, 2018-02-25 (Released:2018-04-14)
参考文献数
37
被引用文献数
1

Because of limitations regarding available statistical data for units of year and enumeration, studies on socio-spatial patterns of Tokyo have not responded sufficiently to the dynamics of the so-called “doughnut phenomenon” period—a combination of urban sprawl and inner city decay—from the late 1960s to the early 1990s. Social maps for 1965 at the cho scale are created using statistics produced separately by the Tokyo Metropolitan Government. These maps are compared to those for 1980, because only the population censuses for 1965 and 1980 enumerate occupation data at this geographical scale. Subsequently, the dynamics of socio-spatial patterns in Tokyo for this period are examined. There were significant changes to names and territories of cho following enactment of the Addressing System Act of 1964. This was a serious problem for creating a social map on the cho scale, which was overcome by allocating either the 1961 cho territory or the current one according to cho name and date of statistics. The results of the analysis demonstrate that, in 1965, white-collar areas were formed as buffers around radial commuting train lines in western Tokyo, and areas between these in outer western Tokyo were not white-collar. Therefore, a star-shaped model, rather than a sector one, is suitable for representing socio-spatial patterns of the inhabitants of Tokyo in 1965. In 1980, the white-collar occupation ratio of these “between” areas rose rapidly, and a sectoral pattern clearly emerged. In eastern Tokyo, almost all areas were blue-collar in 1965, and moderate white-collar areas emerged along radial commuting train lines. The four main reasons for these changes are: 1) housing complex development at the sites of large plants; 2) abolishment of green belt policy; 3) new construction and expansion of radial train lines, especially subway lines; and, 4) expansion of sewage service areas. In western Tokyo, the culvertization of medium and small rivers, around which were former industrial areas, also made an important contribution to transforming blue-collar areas into white-collar areas. These results show the importance of infrastructure development in bringing about socio-spatial changes in Tokyo during this period.