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Volume 46 (2005 - 200･･･
- Issue 6 Pages 311-
- Issue 5 Pages 250-
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Volume 46, Issue 6
Displaying 1-5 of 5 articles from this issue
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Takahito KUROKI, Kozaburo FUKUZUKA, Takashi NOGUCHI2006 Volume 46 Issue 6 Pages 311-319
Published: February 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSWe discussed influence of landslip landforms on rivers in Maetsue area, Hita city, Ooita prefecture. ln this study area, there are 195 landslip landforms, and they were classified into four types by their landforms interpreted by aerial photographs. We considered that existence of cap rock is to be a geologic factor of developing larger landslip landforms in this area.
We investigated relationships between landforms of river and landslip landforms by using stream profile and profile of channel slope. Where larger landslip lobes close to the river, some sections of the stream profile and the profile of channel slope become convex curve caused by aggradations of elevation of river bed. By the form of convex lines on the profile of channel slope, the profile can present more and clearer sections affected by landslip landforms than the stream profile.
Consequently, we consider that we can estimate easily the affected areas by landslip landforms on investigation of such sections of the stream profile. Furthermore, we can indicate the area more clearly from the drawing of the profile of channel slope.
It is easy for us to present the landforms of the river by using GIS software and detailed geographic information.View full abstractDownload PDF (3333K) -
Hidehisa NAGATA, Toru SAKAGUCHI, Satoru KOJIMA2006 Volume 46 Issue 6 Pages 320-330
Published: February 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSWe analyzed the relationship between the distribution of unstable topographic features such as landslides and linear depressions, altitude, and the geology of the area in a 1: 200, 000 sheet map of Gifu using Geographic Information System (GIS). The analyses clarified that unstable topographic features are extensively developed in the areas of the Tetori Group and limestone belonging to the Mino terrane, while they are less developed in the Cretaceous granite. Although granitic rocks in Japan are considered to be one of the lithologies causing few deep-seated landslides, Neogene and Jurassic granites in the study area have more deep-seated landslide topographic features than average. The linear depressions extracted from the topographic maps are divided into two groups: features related in spatial distribution to landslide topographic features and features developed as precursors of future landslides. Thus both the linear depressions and the landslide topography are good indicators of slope instability. Most of the linear depressions seem to have been formed during the dissection stage of the low-relief erosion surface.View full abstractDownload PDF (5099K) -
Limits and Expectations for Natural Hazard Evaluation by 50m-DEMTakehiro OHTA2006 Volume 46 Issue 6 Pages 331-340
Published: February 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSTo evaluate the natural disaster hazards beside the long linear structures such as railways and roads, the investigation must be global, quantitative and economical. Therefore, to discuss the potential of 50m-DEM (Digital Map 50m Grid (Elevation) published by the Geographical Survey lnstitute) for the natural hazard evaluation, the topography of the Miura Peninsula is measured by 50m-DEM. The relationship between the geomorphologic feature of slope failure and the topography and geology of this peninsula is examined based on the topographic parameters calculated from 50m-DEM.
The geology influences the features of topographic parameters. ln addition, the features cannot make clear the geomorphologic feature of slope failure. Therefore, it is difficult to evaluate the slope stability by morphometric measures using 50m-DEM. However, 1 hope for the morphometric measures by 50m-DEM as the primary regional screening investigation, because the 50m-DEM has a uniform precision in widely and is favorable in cost.View full abstractDownload PDF (2411K) -
Kozaburo FUKUZUKA, Masaaki MORI, Yushiro IWAO, Takahito KUROKI, Kazuak ...2006 Volume 46 Issue 6 Pages 341-346
Published: February 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSIn the lowlands under 10 meters in altitude, the northwestern part of Saga plain, we discussed that landforms and landuse changes by using topographic maps, and that relationship between creeks and surface ground by using geologic data. This study reveals that the distribution area of creeks overlaps with the greater part of the soft ground area. Creek is the important geomorphic element that can be estimated the condition of surface ground. Estimating the geology of surface ground by using landform data is an effective estimation method on the ground in the initial road planning at the lowland. The landform data is useful for us not only to reduce the cost for construction but also to use the material on communication in PI (Public Involvement).View full abstractDownload PDF (2864K) -
Takehiro OHTA, Shoichi HACHINOHE2006 Volume 46 Issue 6 Pages 347-360
Published: February 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESS
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