Geomorphological Land Classification Research Articles

Comparison of Geomorphological Land Classification Maps with Flood Hazard Maps at Hachinohe Plain, Aomori Prefecture

Comparison of Geomorphological Land Classification Maps with Flood Hazard Maps at Hachinohe Plain, Aomori Prefecture

Digital archive of geomorphological land classification maps of flood-stricken areas

Digital archive of geomorphological land classification maps of flood-stricken areas

4 海跡湖の湖岸・海底の微地形分類を基礎とした湖沼環境の変化

4 海跡湖の湖岸・海底の微地形分類を基礎とした湖沼環境の変化

地形分類の種類とその問題点 : 「地図と地理認識」 : 1989年度秋季学術大会シンポジウム

地形分類の種類とその問題点 : 「地図と地理認識」 : 1989年度秋季学術大会シンポジウム

Evaluation of Flooding Risk in Greater Dhaka District Using Satellite Data and Geomorphological Land Classification Map

Flood is a common feature in rapidly urbanizing Dhaka city and its surrounding areas. In this research, evaluation of flood risk of Greater Dhaka in Bangladesh has been developed by using an integrated approach of GIS and remote sensing. The objective of the study is to measure the flooding risk based on the satellite data and geomorphological land classification map under the land use/land cover change from 1995 to 2015 related with the urbanization of Dhaka city. Comparing with each landform, land cover unit and historical rainfall data the flooding return period has been calculated. Terrace, natural levee and back swamp has been divided into three sub categories. Especially the built-up zone which is closer to the river channel, former river course and the back swamps are mostly vulnerable to flood inundation. This study revealed that, 70% of Greater Dhaka district within moderate to very high hazard zone, especially surrounding city like Manikganj Sadar Upazila areas. It is expected that, this study could contribute to effective flood forecasting, relief and emergency management for future flood event.

Geomorphological land classification map of Shonai River (Kasugai city) and flood risk assessment using concept of landform

Geomorphological land classification map of Shonai River (Kasugai city) and flood risk assessment using concept of landform

Geomorphological Land Classification Map of the Northern Coast of the Sagami Bay

Geomorphological Land Classification Map of the Northern Coast of the Sagami Bay

DAMAGE ASSESSMENT OF BURIED PIPES DUE TO THE 2007 NIIGATA CHUETSU-OKI EARTHQUAKE IN JAPAN

This study investigated the damage distribution of buried pipes due to the 2007 Niigata Chuetsu-Oki earthquake in Japan. Various damage datasets — e.g. water pipes, low-pressure gas pipes, mid-pressure gas pipes, sewage lines, collapsed houses, and liquefaction occurrences — were integrated into a geographic information system. Using the datasets, the spatial distribution of damage was investigated with respect to geomorphological land classification and altitude. The minimum distances between the damaged locations were measured, and the spatial correlations of damage incidents to lifeline systems were evaluated. In addition, the damage ratios of water distribution pipes were compared with different fragility curves constructed from the damage datasets for the 1995 Kobe earthquake and other recent earthquakes in Japan.

Estimation of spectral amplification of ground motion based on geomorphological land classification

This study aims to estimate the spectral amplification factor for all of Japan. The spectral amplification factor for each geomorphology is calculated from the H/V spectral ratio of the microtremor with the modification factors by Senna et al.(2008). For some geomorphologies, the subdivided units are used. The spectral amplification factor is modeled for each geomorphology. For the 2007 Niigata-ken-chuetsu-oki earthquake, the proposed method is applied. The estimated spectra show good agreements with the observed ones, and the effectiveness of the method is confirmed.

Geomorphologic land classification map of the Mekong Delta utilizing JERS‐1 SAR images

AbstractFlood damage in the Mekong Delta is currently influenced by population growth and the expansion of farmland. The objectives of this study are to describe a method for visualizing flooded areas, classify the geomorphology of the area, and develop a flood‐risk map of the Mekong Delta using Japanese earth resources satellite‐1 synthetic aperture radar (JERS‐1 SAR) data. JERS‐1 SAR data‐processing involves geo‐referencing, image‐noise reduction, re‐sampling, and calculation of the normalized radar cross‐section (NRCS) using TNTmips. Furthermore, we visualized the flooded area of the Mekong River Delta and discussed flood dynamics. The relation between NRCS and micro‐geomorphology was clarified using the geomorphologic land classification map. After evaluating flood risk, we developed a flood‐risk map to visualize the evaluated risk. The differences in NRCS derived from JERS‐1 SAR data were calculated before and after flooding; visualization of the flooded area revealed that the difference between the two datasets was less than − 1·8 (dB). This value was determined from field investigations. We then compiled a map of the flooded area. The relation between NRCS and geomorphology was clarified based on the geomorphologic land classification map. Copyright © 2008 John Wiley & Sons, Ltd.

常時微動のH/Vスペクトル比と地形・地盤分類を用いたスペクトル増幅率の推定

常時微動のH/Vスペクトル比と地形・地盤分類を用いたスペクトル増幅率の推定

ＪＥＲＳ‐１ ＳＡＲ画像解析によるメコンデルタの洪水リスク評価

The Mekong delta is experiencing flood damage at a time when the population is growing and farmland is expanding. Because the Mekong River Delta is one of the important grain belts in Vietnam, planning disaster mitigation is government policy. The purposes of this study are to present a method of visualizing flooded areas, classify geomorphology, and make flood risk map using JERS-1 SAR of the Mekong River Delta. JERS 1 SAR data, including geo-reference, noise reduction, re-sampling, and calculation of Normalized Radar Cross Section (NRCS), were processed by TNTmips. The flooded area in the Mekong River Delta is visualized and flood dynamics are discussed. The relation between NRCS and micro-geomorphology was clarified by a field investigation and a geomorphologic land classification map is presented. After evaluating flood risk in four levels, a flood risk map was created by visualizing the evaluation. Differences between NRCS of JERS 1 SAR before and after a flood are calculated, and the flooded area is visualized for differences lower than - 1.8 (dB). This value (-1.8 dB) was defined by a field investigation. Flooded area maps for 1995, 1997, and 1998 were created. The relation between NRCS and geomorphology was clarified by field investigations, and a detailed geomorphologic map in the Mekong delta was created with reference to the geomorphologic land classification map.

全国地形分類図による表層地盤特性のデータベース化, および, 面的な早期地震動推定への適用

We developed digital maps of the geomorphological land classifications and the site amplification factors in Japan, and applied them to strong motion estimations immediately after earthquakes. For making the maps, we first digitized the geomorphological land classification maps of Japan (1:200, 000 or 1:100, 000 scale) and constructed 500m mesh data. Then, we made up the maps of site amplification factors using the empirical relation by Midorikawa and Matsuoka (1995). We evaluated their accuracies by comparing the estimated strong ground motions with the records of K-Net for recent earthquakes in the Kanto area. We estimated the strong motions using the site amplification factors and the two methods: the attenuation relation (Si and Midorikawa, 1999), and an interpolation method using the records. We found that the second method gave more reliable results than the first method, because the first method strongly depended on accuracies of the source and path effects. However, since we may not be able to obtain quickly strong motion records near highly damaged areas, it would be efficient to evaluate the strong motions using the first method immediately after an earthquake, then to replace them by the second method after getting the records. Finally, we compared the site amplification factors using the following two methods. The first is based on the average of shear wave velocities from the free surface to the 30m depths using boring data. The second is the above-mentioned method based on the land classifications. The comparisons showed that the first method was more accurate and reliable. Therefore, it is necessary to replace the digital maps of the site amplifications by those using the first method, when we obtain boring data.

Relationship between geomorphological land classification and site amplification ratio based on JMA strong motion records

The relationship between the amplification ratio of earthquake ground motion and geologic conditions at Japan Meteorological Agency (JMA) stations nationwide was examined to propose an estimation method of the amplification ratio that is applicable to entire Japan. The amplification ratios for the instrumental JMA intensity, as well as for the peak ground acceleration and velocity, were obtained from the station coefficients of the attenuation relationships using strong motion records measured at 77 JMA stations over a period of more than 8 years. A combined use of geomorphological land classification and subsurface geology was found to yield the best estimate of the site amplification ratio. This result suggests that these data, and hence the Digital National Land Information, which is a nationwide GIS database, may be conveniently used for the estimation of strong motion distribution over large areas in Japan.

Geomorphological zoning for flood inundation using satellite data

The authors investigated geomorphological features on the central plain of Thailand utilizing satellite remote sensing data and made geomorphological land classification map showing flood-stricken area. Land classification maps showing flood-striken area tell us former flood inundation area, such as inundation depth, inundation width, flood flow course and flood direction, as well as estimating of the features of flooding. Thus map is useful for planning of flood control works.

1987年千葉県東方沖地震の地震動応答スペクトルにみられる地盤特性の評価

Site effects on response spectra of ground motions observed at 173 sites during the 1987 Chiba-ken-toho-oki earthquake (M = 6.7) were evaluated. The results indicate that 1) the site effects are significant on motions with periods longer than 0.2 second, 2) geomorphological land classification is more appropriate for evaluating the site effects than soil classification or surface geology, 3) the site amplifications at longer periods have stronger dependence on the average shear-wave velocity of ground, and 4) the average shear-wave velocity is a useful predictor for the site amplifications at periods of 0.7 to 1.5 seconds.

国土数値情報を利用した広域液状化危険度予測

A system for liquefaction potential mapping of a hypothetical earthquake is built up using the Digital National Land Information as the GIS application to seismic hazard prediction for a large area. A geomorphological land classification map which is useful for. evaluating liquefaction susceptibility is compiled from the topographical information which is easily available from the Digital National Land Information. The liquefaction potential map is developed by overlaying two maps : the land classification map and an isoseismal map which is expressed in peak ground velocity. The predicition is conducted for the 1987 Chiba-ken-toho-oki earthquake, and shows good agreement with observations of liquefaction in the earthquake.

A Geomorphologic Land Classification Map Indicates an Active Fold of the Shonai Plain, Northeast Japan

Shonai Plain is located in the lower reach of the Mogami River, which flows into the Japan Sea in Northeast Japan. The Amarume Anticline, where Amarume and other oil fields are located, runs from north to south in the eastern part of the plain. Deformations of the plain surface are seen as evidences of an active fold on this plain.During the revision of the “Geomorphologic Land Classification Map of the Shonai Plain illustrating features of flooding and soil liquefaction” (Oya et al., 1982, 1989), it was found that the Amarume Anticline influenced the river courses in the Shonai Plain. By studying historical maps based on a geomorphologic land classification map, I found that the Mogami River has changed its course repeatedly within a entrenched meandering belt of the river along the Amarume Anticline from 17th century to the present. The relative height of a natural levee from the former Mogami river bed is 2.65m along the anticline. Furthermore, the Aizawa River, a small tributary which flows into the Mogami River near Sagoshi, is entrenching the alluvial surface of the plain with its relative height of 4.5m. The Kyoden River from Mt. Haguro shows an incised meander along the Amarume Anticline. These phenomena descrived above can be used to determine the existence of an active fold—Amarume Anticline.Geomorphologic land classification maps serve many purposes. For example, one was used to determine the site of bridge at the Brahmaputra-Jamna River by Oya (1979). Geomorphologic land classification maps can also be used to indicate the presence of an active fold. Moreover, they illustrate how river cources change with time.

Seismic microzoning on soil liquefaction potential based on geomorphological land classification : Kotoda, K; Wakamatsu, K; Midorikawa, S Soils FoundV28, N2, June 1988, P127–143

Seismic microzoning on soil liquefaction potential based on geomorphological land classification : Kotoda, K; Wakamatsu, K; Midorikawa, S Soils FoundV28, N2, June 1988, P127–143

地形分類を基礎とした日本と韓国の河成平野の比較研究

We have conducted a comparative research on the fluvial plain between Japan and South Koreabased on geomorphological land classification. There are distinct regional differences in thegeomorphology of Japan and South Korea even though they are adjacent to each other. The fluvialplains in Japan are depositional plains, but in South Korea they are basically erosional plains, eventhough they are thinly covered with sand and gravels. Based on the combination of geomophological elements, the plains of Japan and South Korea areclassified as follows: <Japan> (“On” group =basic form) Fan+Natural Levee (Back Marsh)+Delta.(“Od” group) small fan+small natural levee+Delta no fan+no natural levee+Delta. <Korea> (basic from) Pediment+Pen-pediment+Natural Levee (Back Marsh)+Tide land.(R. Naktong) Pediment+Peri-pediment+Natural Levee (Back Marsh)+Delta+Tide land. The above outlined differnces were formed by the following factors: 1) In Japan, erosion in the mountainious region is pronounced due to the steep topography andbecause of the torrential rainfall. Sand and gravels were supplied to the valley bottom by land collapses and transported to the plainby rivers during the flood season. They were deposited at the boundary between the mountainousregion and plains, and formed fans. In South Korea, a great deal of fine-grained material is produced because of the wide distributionof gneisses and granitic rocks which are easily weathered and by mechanical weathering in themountainous region due to the low temperatures during the winters. The debris which was formed onthe surface of the mountanious regions was washed away by torrential rainfall during the summerseason. The gravels were deposited on the gentle piedmont slopes, especially the lower parts ofpediments which were thinly covered with sand and gravels were formed as peri-pediments. 2) The coefficients of river regimes are large in the rivers of both countries. The ratio in Korea islarger than that of Japan. The longitudinal profile of rivers in Japan is steeper than that of Korea. Due to the above mentioned features of the rivers, a great deal of sand and gravel was transportedin Japan and sand were transported in South Korea, so that natural levees are developed better in South Korea than in Japan. 3) In Japan, the deposition of sand and gravels a t the lowest reaches is remarkable. Because manyrivers pour into inland bays, many big deltas are formed in the lowest reaches. In South Korea, the deposition of sand and gravels in the lowest reaches is difficult partly becausethe rivers pour into the open sea directly, and partly because of the very wide tidal range, for example 8.1m at the lowest reach of the Han River. 4) The differences between the two groups based on the combination of geomorphologicalelements in Japan are related to whether a river has intermontane depressions and gorges in the upperreaches or not: the “On” group has no intermontane depressions or gorges in the upper reaches, whilethe “Od” group has. The differences in the combination of geomorphological elements in Korea are based on naturalconditions at the river mouth.