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新潟県古志郡山古志村における虫亀地すべりの形態とその形成過程
http://hdl.handle.net/10191/39002
http://hdl.handle.net/10191/390028b1fb001-16c2-480d-99c4-7dcd9ceae645
| 名前 / ファイル | ライセンス | アクション |
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3_1-21.pdf (1.6 MB)
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| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
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| 公開日 | 2016-03-03 | |||||
| タイトル | ||||||
| タイトル | 新潟県古志郡山古志村における虫亀地すべりの形態とその形成過程 | |||||
| タイトル | ||||||
| タイトル | 新潟県古志郡山古志村における虫亀地すべりの形態とその形成過程 | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| その他のタイトル | ||||||
| その他のタイトル | Surface and subsurface structure of landslide mass and their forming-process in the Mushigame landslide, Koshi-gun (County), Niigata Prefecture, Central Japan | |||||
| 著者 |
藤田, 至則
× 藤田, 至則× 茅原, 一也× 青木, 滋× 鈴木, 幸治 |
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| 著者別名 | ||||||
| 識別子Scheme | WEKO | |||||
| 識別子 | 162088 | |||||
| 姓名 | Fujita, Yukinori | |||||
| 著者別名 | ||||||
| 識別子Scheme | WEKO | |||||
| 識別子 | 162089 | |||||
| 姓名 | Chihara, Kazuya | |||||
| 著者別名 | ||||||
| 識別子Scheme | WEKO | |||||
| 識別子 | 162090 | |||||
| 姓名 | Aoki, Shigeru | |||||
| 著者別名 | ||||||
| 識別子Scheme | WEKO | |||||
| 識別子 | 162091 | |||||
| 姓名 | Suzuki, Koji | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | At 04^h05^m-10^m on 9th April, 1980, the slope area of about 2500 ha, located at 450m above the sea level, was broken and mass of about 1,200,000m^3 slid down the small valley (Takino-bayashi-gawa, a branch of Asahi-gawa) in the Mushigame area. The landslide area is on a scale of 50～200 m in width, 1,500 m in length along the slope, 20 m in depth in maximum and 250 m in drop height. It is important that the first sliding plane was not within the bed rock of Shiiya Formation of Miocene age, but in the debris deposit covering the bed rock. The normal faults (lunar fault crack) are developed mostly behind the crown of the main scarp (Fig.4). Among them, some faults have been formed before the event, and the others during or after the sliding. Those normal faults dip in the same direction as that of sliding scarp. Many scratching streaks were formed on the steep left flank scarp (Photo. 8). The potential energy was converted to kinetic one to make the affected blocks on foot slide down the valley, along which the adjoining blocks flew down successively about 250 m in vertical height and about 1500 m in horizontal distance. The primary and secondary slide blocks and debris cover the area of 250m (upstream) and 150m (downstream) wide and about 1.5 km long and of 25×10^4m^2. The total volume of slide mass is estimated to be about 1.2×10^6m^3, excluding that of flowing away (Fig. 2). By this event, two roads, farmland and forest of about 20.5 ha suffered severe damage. The topography, geology and structural features, especially pre-existing normal faults system genetically related to sliding, features of sliding and flowing blocks, were surveyed by the present writers. The description above is followed by some discussion on the trigger of sliding and the mechanism of forming-process of minor faulting developed on the surface of the sliding blocks. The slide deposits area divisible into the following four parts; (1) the upbulge at the foot of main scarp, (2) uppermost affected area, (3) successive upper to lower area, and (4) lowermost muddy flow and deposit area. The surface inclination of each slide blocks are 30-35 in (2), 15-20 in (3) and 10 in (4) respectively. The removed distance in (2) area was about 80-150m, and that in (3) area about 200m as clearly seen from the displacement of road and electric pole (Fig. 3). The landslide debris formed during the present event are divided into two types of distribution; lateral and central debris. The former is composed mainly of fragments of mudstone derived from sliding wall rock. Its form of piling up are very similar to that of mudflow Ievee. The latter commonly covers the former, suggesting the later flowing than the former. The width of central debris is 200m in the upper part, 100-150m in the middle and 50-60m in the lower stream. The thickness of central debris is 20m on average, being thinner on upside and thicker on the down slope. The surface of sliding soil mass is cut by a large number of normal fault (similar to transverse crack) to tilt the divided blocks (Figs.5, 6) Those surfaces originally covered the upstream affected area before sliding. | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | The surface of landslide debris consists of what were originally the older one covering the affected land before the event, and the newly formed (exposed) one corresponding to fault plane. Two types of normal faulting are distinguished; landslide parallel normal fault dipping upstream side and landside crossed normal fault inclining to the opposite side. Most of original surface incline toward the upstream side at five areas, but some one in the opposite direction to it, which developed onIy in some limited parts of sliding mass. Some eyewitness said that the level of sliding surface were 20-30m higher than that after stopping, and that the surface of sliding mass were first smooth, and then yielded the irregular surfaces during the process of fixing. Those fact shows that the displacement of each blocks by normal faulting was caused during the process of lowering of the sliding surface. The genesis of normal faults formed on the surface of central debris is reasonably assumed to have formed by tension acting during flow down of sliding mass. The supposed mechanism is proved by observation of eyewitness that the sliding surface was very flat and smooth at the early stage of sliding and then became struggy. By these faulting the sliding mass was drawn as a whole. The phenomenon may be interpreted as nearly the same process proposed from an experiment made by H.Cloos (1939) who distinguished two types of fault, synthetic and antithetic faults. The surface of central landslide debris shows some transverse ridge apart abut 50-100m from each other. Those higher parts may represent the tips of each sliding units blocks or may have deveIoped on a underground obstacle of bed rock, and or may be caused by the collision of different debris blocks. Our analysis of the normal fault pattern may make it possible to presume the secondary slide plane (second surface of rupture) (Fig. 11). There is a large possibility that the landslide was triggered by the following sequence, first rapid melting of snow due to extraordinary high atmosphere temperature and rain fall on some days preceding the sliding; secondary by the following rapid rising of pore pressure caused by rapid infiltration of water into underground through faults; and thirdly the development of many normal faulting around the sliding scarp.. These normal faults were considered to have been formed successively from downside to upward. | |||||
| 書誌情報 |
新潟大学積雪地域災害研究センター研究年報 en : 新潟大学積雪地域災害研究センター研究年報 巻 3, p. 1-21, 発行日 1981-11 |
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| 出版者 | ||||||
| 出版者 | 新潟大学積雪地域災害研究センター | |||||
| ISSN | ||||||
| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 03877892 | |||||
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| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AN00183327 | |||||
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| 値 | publisher | |||||
