Proceedings of the General Meeting of the Association of Japanese Geographers

In the 1970's from globe interiors like balloons format appeared. Materials make classroom issues and draw map sphere onto the plane and, utilizing a variety of map projections reveal a realistic image of the Earth, whereas every time. Stands for map drawing practice utilizing the mental map = mind map. Was in the subject of a new era in ties and globalization. Soft Globes appearances and use brought the PC in the classroom teaching, ICT diffusion before science and society, geography civics Department subjects teaching design became a plus.

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Topography of mountainous rivers may record signals of tectonics, climate history or bedrock lithology. Steepness of rivers should be controlled by uplift rate and bedrock resistance, and can be quantified by means of slope-area analysis and/or chi-plot analysis, both of these methods are built in the basis of stream-power incision model. Chi-plot analysis of rivers at Yoro Mountains and Suzuka Mountains revealed spatial variability of river steepness. At Yoro Mountains, trend of river steepness variability is concordant with ridge-line altitude, roughly represents long-term uplift rate.

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In this study, diurnal variation in occurrence frequency of summertime localized intense rainfall in the Tokyo metropolitan area were analyzed by using spatially dense rain gauge network.

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2015 Typhoon Kilo and Etau gave heavy rain in early September in Ibaraki and Tochigi Prefectures, in Japan, and caused the flood in Joso and Shimotsuma Cities, Ibaraki Prefecture. I sampled both flood sediment and natural levee deposits at the dike-broken site (Kami-misaka, Joso City) in Kinugawa River, and sampled flood sediment and river bank dune deposit at the overflow site (Waka-miyado, Shimotsuma City) in the River, then tried to understand the characteristics of the flood by investigating grain size distribution of the deposits. Near the dike-broken site, I found the possibility that flood deposit is the mixture of medium sand derived from waterside land and fine sand derived from natural levee where is incised by flood grooves. At the site ca. 350m away from the dike-broken site, two types of deposits were found; one is that medium sand was mainly deposited and another case is that medium sand was deposited on the surface and underlying mixture of medium and fine sand, it is thought to prove that flood stream flew and eroded on the natural levee. Grain size distribution of suspended sediment deposit at the overflow site resembles that of natural levee deposit at the dike-broken site; however, suspended sediment deposit contains more silt than natural levee deposit, therefore I pointed out that depositional environment of natural levee was different from that of the suspended sediment deposit by the flood. Furthermore, it was found that that grain size distribution of river bank dune deposit resembles that of medium sand deposit caused by the flood, and I pointed out the possibility that environment of sediment source of the river bank dune resembled that of current river bank.

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