地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
115 巻 , 5 号
選択された号の論文の11件中1~11を表示しています
  • 藤原 治, 小松原 純子, 高田 圭太, 宍倉 正展, 鎌滝 孝信
    2006 年 115 巻 5 号 p. 569-581
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    The temporal development of a late Holocene strand plain system along the western Shizuoka Prefecture was reconstructed based on facies analyses and 14C dating for core samples excavated in a back marsh using a geo-slicer, 6.0-m-long, 0.35-m-wide, and 0.05- to 0.1-m-deep wedge-shaped stainless steel case. The strand plain system consists of beach, sand dune, and back marsh. Stratigraphic succession of the strand plain system, up to 4.4 m thick, is composed of upper shoreface sand, foreshore sand, backshore sand, and back marsh mud, in ascending order. The succession shows three development stages of the strand plain system.
    Stage 1 (before the 13th century) : The study area was under a wave-dominated beach environment. The beach system was developed by progradation of shoreface, foreshore, and backshore deposits in the later period of this stage.
    Stage 2 (from the 13th century to the 16th century) : Sand dune and back marsh developed, covering the beach deposit. Humic mud was thickly deposited in the back marsh with low sand supply from seaward across the dune.
    Stage 3 (after the 17th century) : The back marsh has been infilled mainly by washover sand and debris from the hinterland. The AD 1707 Hoei Earthquake Tsunami, which destroyed villages on the dune, possibly promoted reactivation of sand movement from ruined dune to the back marsh.
  • 竹中 克行
    2006 年 115 巻 5 号 p. 582-605
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    In-migration to Barcelona in the twentieth century was not only a population influx from rural Spain, but an incoming of people imbedded with a distinct cultural and linguistic background from that of the local Catalan-speaking people. This article analyzes the impact of in-migration on the configuration of residential areas in Barcelona from 1970 to 1991; that is, twenty years from the decline of the migratory inflow until the arrival of a period of intensive urban renewal. Among the various steps of the analysis, geographical origin as a cohesive factor of the residing population is contrasted with two other factors : professional status and lifecycle.
    A multivariate analysis applied to the population of census tracts draws quite a clear picture of four clusters defined by geographical origin, but none of them is composed of exclusive urban spaces occupied only by people of a specific origin. Furthermore, the distribution of the four groups shows considerable overlaps with that of professional clusters and that of lifecycle clusters, so segregation by geographical origin is, to a certain degree, due to different socioeconomic compositions found among the four groups. This interpretation is supported also by another analysis based on the index of dissimilarity, by which the effects of various socioeconomic variables on residential patterns are statistically evaluated.
    After clustering the dwellings of Barcelona by a similar method to that applied to the population, a cross-tabulating analysis reveals that the living conditions of the dwellers show a remarkable disparity by groups of different geographical origin-a disparity related not only to the qualitative aspects of the dwellings themselves, but to the situation and the accessibility of the neighborhood in which they are inserted. However, differences in socioeconomic composition mentioned above are also behind the unfavorable conditions of the newcomers, which in turn have been experiencing major changes through improvements in housing equipment and also in the surrounding infrastructure.
  • 松山 洋, 北村 彩子, 泉 岳樹
    2006 年 115 巻 5 号 p. 606-625
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    Thermal infrared images observed by satellites are affected by atmospheric absorption and emission. Due to a lack of data, previous studies used at most one atmospheric vertical profile to retrieve surface temperature. In this study, atmospheric correction was performed using MODTRAN, with which the effects of the spatial distribution of atmosphere were considered. Five summer scenes and four winter scenes of Landsat-5/TM and -7/ETM+ (Kanto scene, Path 107/ Row 35), aerological data at Tateno, and regional objective analysis data with ca. 20 km spatial resolution were used. Effects of atmospheric correction were evaluated from the surface temperature estimated by upward longwave radiation at Tateno. Also, the effects of spatial variations of atmospheric transmissivity on surface temperature were evaluated.
    The regional objective analysis data were adequate for input to MODTRAN. The differences among atmospheric corrections estimated from aerological data at Tateno and regional objective analysis data, were large in summer (ca. -5.2-12.0°C) and small in winter (ca. -1.9-0.9°C).The differences increased with both surface temperature and atmospheric water vapor content. Considering the accuracy of MODTRAN (ca. 1-2°C), it is necessary to take into account the spatial distribution of the atmosphere in summer. In winter, aerological data at Tateno represented the condition of the whole of the Kanto scene; therefore, it is not necessary to consider the spatial distribution of the atmosphere for atmospheric correction.
    In summer, the spatial variation of atmospheric transmissivity of 0.01 was comparable to 1°Cof the surface temperature. While in winter, the spatial variation of atmospheric transmissivity of 0.04 was equivalent to 1°C of the surface temperature. These results were clarified by the present study for the first time.
  • 吉原 一城, 小松 俊文
    2006 年 115 巻 5 号 p. 626-637
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    The geology and the paleontology of the Cretaceous Misakubo Formation have been investigated. The Misakubo Formation is narrowly distributed along the eastern side of the Sambagawa Belt and the Miocene Tokizawa Formation in the northern part of Misakubo, Hamamatsu, Shizuoka Prefecture. This formation consists mainly of black mudstone, fossils yielding bivalves, ammonoids, gastropods and crinoids. Late Albian mid-Cretaceous ammonoids such as Mortoniceras rostratum, Desmoceras latidorsatum, Desmoceras sp., Mariella sp., and Lechites sp. are found in the upper part of the formation. Shallow marine bivalve assemblage yielded in the formation is predominated by Pterotrigonia pustulosa. The fossil bivalve assemblage is compositionally similar to the inner shelf assemblages of the Enokuchi Formation of the Goshoura Group; the Miyanohara Formation, the Fukkoshi Formation and the Nagase Formation of the Sotoizumi Group and the Mikasa Formation of the Yezo Group. The range of these trigoniids might be incorrect, because Pterotrigonia mifunensis and Pterotrigonia monobeana yielded with M. rostratum.
  • 吉田 英嗣, 須貝 俊彦
    2006 年 115 巻 5 号 p. 638-646
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    Asama volcano, whose present highest altitude is 2568 m above sea level, and which is a typical Quaternary stratovolcano in Japan, collapsed at approximately 24 ka. The sediment originating from this collapse event has been recognized in far distant areas by mineralogical, lithological, and tephrochronological research. A collapsed sector often moves as a debris avalanche, which consists of debris-avalanche blocks and debris-avalanche matrix. The debris-avalanche blocks form a hummocky topography, which indicates the flow under relatively dry conditions. To deduce the nature of the debris transport event to be clarified, this paper shows the morphological characteristics of hummocks. Hummocks formed by the Asama volcano collapse at 24 ka are distributed over Ohkuwa, Karuizawa, Saku, and Nakanojo districts within 45 km from the source. Their sizes are larger as approached to the source, indicating the debris-avalanche blocks were disaggregated irreversibly according to travel distance. This means the debris flowed as a debris avalanche in Nakanojo district, even though the debris had channelized into the Agatsuma River valley. Also, there is expected to be an exponential relation between distance from source and length of major axis of a maximum hummock in each region. Although no hummocks are recognized in the northwestern corner of the Kanto Plain, some blocks at least 5-15 m across are observed in the deposits. If we extrapolate downstream the above exponential relation, similar values for the sizes of these blocks can be acquired in the northwestern corner of the Kanto Plain. This size-distribution shows the possibility that the collapsed materials reached the northwestern corner of the Kanto Plain as a single debris transport event.
  • 加藤 幸弘
    2006 年 115 巻 5 号 p. 647-651
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    Under the United Nations Convention on the Law of the Sea (UNCLOS), coastal states shall establish the outer limit of the continental shelf beyond 200 nautical miles when coastal states fulfill a number of geomorphological and geological criteria. Coastal states must submit information including scientific data defining the outer limits of the continental shelf to the UN Commission on the Limits of the Continental Shelf (CLCS). Therefore, coastal states need to acquire and analyze large volumes of geological and geophysical data.
    To prepare the necessary information by the time limit, which is May 2009 for Japan, survey work, including surveys of crustal structure, bathymetric survey, and ocean bottom sampling, have been conducted under the coordination of an inter-ministerial council.
  • 大場 忠道
    2006 年 115 巻 5 号 p. 652-660
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    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.
  • 田村 俊和, 守屋 以智雄, 長谷 紘和
    2006 年 115 巻 5 号 p. 661-665
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 2006 年 115 巻 5 号 p. e1
    発行日: 2006年
    公開日: 2010/11/18
    ジャーナル フリー
  • 苅谷 愛彦
    2006 年 115 巻 5 号 p. Plate1-Plate2
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 苅谷 愛彦
    2006 年 115 巻 5 号 p. Plate3-Plate4
    発行日: 2006/12/25
    公開日: 2009/11/12
    ジャーナル フリー
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