Flexural-slip faults are distributed in the western part of the Shinjo Basin, Yamagata Prefecture. The Nikke and Masugata faults are flexural-slip faults accompanying flexural-folding by the Sakekawa blind reverse fault. The Nikke fault ruptured after 20ka. The Masugata fault ruptured before 50ka, but there is no indication of fault event after 50ka. Flexural-folding that had caused the Masugata fault has been inactive since 50ka because faulting is migrated from the Sakekawa fault to the Motoaikai fault. Therefore, the two flexural-slip faults have not ruptured simultaneously since 50ka.

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山形県新庄盆地に分布する中期更新世後半のテフラ層序を示し,奥羽山脈東側の地域に分布するテフラとの対比を試みた.テフラの対比にあたって,構成物質および屈折率特性の層内垂直変化に着目した.主なテフラは下位より,西山テフラ (Nsy), 鳥越テフラ (Trg), 二枚橋テフラ (Nmb), 泉川テフラ (Izk), 絵馬河テフラ(Emk),牛潜テフラ (Usk) が累重する.Nsy, TrgおよびEmkは奥羽山脈東側にも分布し, Trg, Emkは鬼首池月テフラ (O-Ik), 曲坂テフラ(MgA)にそれぞれ対比される.Uskは上位にあるレスの堆積速度を一定と仮定すると,200～230kaに噴出したと推定される.新庄盆地を埋積する中部更新統山屋層は,O-Ik噴出以降,Nmb噴出前後に堆積が終了し,その年代は300ka前後と推定される.

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In the luminance distribution of a lit sign, having no irregularities in brightness is desirable, that is, the uniformity ratio of the luminance should be good. The uniformity ratio is decided by various factors such as the number of lamps, the spacing of the lamps, the distance between the light source and the luminous surface, the inner surface reflectance, and the luminous surface reflectance. A simple prediction method to obtain the relationship between these factors and the uniformity ratio of the luminance was tested by using calculations on a two-dimensional surface. We found that the method was suitable, because the calculated and experimental results agreed with each other.

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Kitahara tephra (Kth) and Dokusawa tephra (Dks) are Late Pleistocene tephra layers containing biotite and cummingtonite characteristically. Kth is distributed on the eastern side of the Ou Ranges and Dks is on the western sides of the Ranges in the central part of Northeast Japan. Vertical variations of modal amounts, refractive indices and major element chemistry of minerals and mineral assemblages were examined on Dks and Kth. Cummingtonite shows nearly constant variation in the refractive indices and Mg-values [Mg/(Mg +Mn+ Fe)]. On the contrary, the refraetive indices and Mg-values of orthopyroxene and hornblende have wide variations. Dks and Kth correlate with each other because the refractive indices and chemical composition of cummingtonite are quite similar. "Atago tephra" containing a lot of high-quartz can be correlated with the lower unit of Kth because high-quartz is included in both tephras. Dks comprises cummingtonite, biotite, high-quartz and epidote as a whole layer. The upper part of Dks also includes orthopyroxene, clinopyroxene and hornblende. The mineral composition of Kth resembles the upper part of Dks and does not show vertical variation. These facts indicate that the upper part of Dks is distributed on both sides of the Ou Ranges.

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Topography has dominant effects in hydrological modeling. The purpose of this study is to explore a proper subdivision level for distributed hydrological model BTOPMC (Block-wise use of TOPMODEL with Muskingum-Cunge method), so that simulation uncertainty due to basin subdivision could be reduced to quite a low level. The Pfafstetter subdivision algorithm was successfully integrated into the model and related problems and solutions were discussed. Using this BTOPMC, the effects of sub-basin scale on runoff simulations were investigated for the Fuji-kawa and the Nakagawa basin, respectively. It was found that as the average area of sub-basins becomes smaller, the simulated total runoff usually tends to be increased in flood/wet period and decreased in dry period, this is considered as the effect of averaging scale of the topographic index in the model. However, the results indicated that model performance appears stabilized when average sub-basin scale is about 1/150 of the entire basin.

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