• Title/Summary/Keyword: ZONATION

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Forest Fire Risk Zonation in Madi Khola Watershed, Nepal

  • Jeetendra Gautam
    • Journal of Forest and Environmental Science
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    • v.40 no.1
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    • pp.24-34
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    • 2024
  • Fire, being primarily a natural phenomenon, is impossible to control, although it is feasible to map the forest fire risk zone, minimizing the frequency of fires. The spread of a fire starting in any stand in a forest can be predicted, given the burning conditions. The natural cover of the land and the safety of the population may be threatened by the spread of forest fires; thus, the prevention of fire damage requires early discovery. Satellite data and geographic information system (GIS) can be used effectively to combine different forest-fire-causing factors for mapping the forest fire risk zone. This study mainly focuses on mapping forest fire risk in the Madikhola watershed. The primary causes of forest fires appear to be human negligence, uncontrolled fire in nearby forests and agricultural regions, and fire for pastoral purposes which were used to evaluate and assign risk values to the mapping process. The majority of fires, according to MODIS events, occurred from December to April, with March recording the highest occurrences. The Risk Zonation Map, which was prepared using LULC, Forest Type, Slope, Aspect, Elevation, Road Proximity, and Proximity to Water Bodies, showed that a High Fire Risk Zone comprised 29% of the Total Watershed Area, followed by a Moderate Risk Zone, covering 37% of the total area. The derived map products are helpful to local forest managers to minimize fire risks within the forests and take proper responses when fires break out. This study further recommends including the fuel factor and other fire-contributing factors to derive a higher resolution of the fire risk map.

Seismic Site Classes According to Site Period by Predicting Spatial Geotechnical Layers in Hongseong (홍성 지역의 공간 지층정보 예측을 통한 부지주기 토대의 지진공학적 부지분류)

  • Sun, Chang-Guk
    • Journal of the Korean Association of Geographic Information Studies
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    • v.13 no.4
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    • pp.32-49
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    • 2010
  • Site characterization on geological and geotechnical conditions was performed for evaluating the earthquake ground motions associated with seismic site effects at a small urbanized area, Hongseong, where structural damages were recorded by an earthquake of magnitude 5.0 on October 7, 1978. In the field, various geotechnical site investigations composed of borehole drillings and seismic tests for obtaining shear wave velocity profile were carried out at 16 sites. Based on the geotechnical data from site investigation and additional collection in and near Hongseong, an expert system on geotechnical information was implemented with the spatial framework of GIS. For practical application of the GIS-based geotechnical information system to assess the earthquake motions in a small urban area, spatial seismic zoning maps on geotechnical parameters, such as the bedrock depth and the site period ($T_G$), were created over the entire administrative district of Hongseong town, and the spatial distributions of seismic vulnerability potentials were intuitively examined. Spatial zonation was also performed to determine site coefficients for seismic design by adopting a site classification system based on $T_G$. A case study of seismic zonation in the Hongseong area verified that the GIS-based site investigation was very useful for regional prediction of earthquake ground motions in a small urbanized inland area.

Subtidal Zonation of the Cumacean Bodotria biplicata in the Surf Zone of Dolsando, Southern Korea (돌산도 쇄파대에 사는 쿠마류 Bodotria biplicata의 조하대 대상분포)

  • SUH Hae-Lip;KOO Young Kyung
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.1
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    • pp.39-45
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    • 1997
  • Subtidal zonation of a cumacean Bodotria biplicata was investigated in the sandy shore surf zone of Dolsando, southern Korea. Three replicate samples were taken with a sledge net at three sites, such as the surface and bottom of 1 m depth and waters edge, at hourly intervals over the neap and spring tide cycles on January 1993 (n=225). B. biplicata, the most dominant cumacean in this area, exhibited peak density at the bottom while about $0.6\%$ of total catch was collected at the surface. Mean density during the neap tide cycle was slightly higher than that during the spring tide cycle. The depth of subtidal zone influenced the total catch of B. biplicata. The changes in density were related to the depth of subtidal zone rather than day-night cycle or ebb-flood tide. The results obtained in this study suggest that the diel vertical migration is not distinct. During both neap and spring tide cycles, B. biplicata attained a density maximum at the same level of about 90 cm below lower low water (LLW). It is likely, therefore, that this species performs shore- and seaward horizontal migration fortnightly. The speed and distance of migration may be directly related to the beach slope and tide range. Ontogenetic differences in subtidal distribution were observed. Juveniles and manca larvae tended to occur lower areas than the adults. Such differences may reduce intraspecific competition for diets.

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Winter Zonation of the Benthic Amphipods in the Sandy Shore Surf Zone of Dolsando, Southern Korea (돌산도 모래해안 쇄파대에 사는 저서성 단각류의 겨울철 대상분포)

  • SUH Hae-Lip;Yu Ok-Hwan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.3
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    • pp.340-348
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    • 1997
  • Sledge net samples were taken over the neap and spring tide cycles in January 1993 from the bottom and surface of 1 m depth and at the water's edge in the sandy shore surf zone of Dolsando, southern Korea. Zonation pattern of three dominant gammarid amphipods was compared. The amphipods were more abundant on the bottom and at water's edge than in the surface. Average densities at both sites of Pontogeneia rostrata and Allorchestes angusta were higher during the neap tide than the spring tide, whereas that of Synchelidium lenorostralum was lower during the neap tide. P. rostrata migrated horizontally during the flooding and ebbing tides, but S. lenorostralum and A. angusta did not. Unlike other species, P. rostrata was significantly more abundant at night, suggesting its active nocturnal movement. During flooding tide, P. rostrata was not found on the shore above the mean sea level (MSL) during daytime, but found in 100 cm above MSL at night. Zonal distribution of P. rostrata which was restricted from MSL to 250 cm below MSL, however, did not vary with the day-night cycle during ebbing tide. S. lenorostralum and A. angusta were not found during flooding tide but ebbing tide. The upper distribution limit of the former was 150 cm below MSL, and the distribution of the latter ranged from MSL to 150 cm below MSL. The highest densities of P. rostrata, S. lenorostralum and A. angusta were 32, 26 and 3 ind. $m^{-2}$, respectively. We discussed the relationships between the distribution pattern of three dominant species of gammarid amphipods and their life styles in the sandy shore.

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Seismic Zonation on Site Responses in Daejeon by Building Geotechnical Information System Based on Spatial GIS Framework (공간 GIS 기반의 지반 정보 시스템 구축을 통한 대전 지역의 부지 응답에 따른 지진재해 구역화)

  • Sun, Chang-Guk
    • Journal of the Korean Geotechnical Society
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    • v.25 no.1
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    • pp.5-19
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    • 2009
  • Most of earthquake-induced geotechnical hazards have been caused by the site effects relating to the amplification of ground motion, which is strongly influenced by the local geologic conditions such as soil thickness or bedrock depth and soil stiffness. In this study, an integrated GIS-based information system for geotechnical data, called geotechnical information system (GTIS), was constructed to establish a regional counterplan against earthquake-induced hazards at an urban area of Daejeon, which is represented as a hub of research and development in Korea. To build the GTIS for the area concerned, pre-existing geotechnical data collections were performed across the extended area including the study area and site visits were additionally carried out to acquire surface geo-knowledge data. For practical application of the GTIS used to estimate the site effects at the area concerned, seismic zoning map of the site period was created and presented as regional synthetic strategy for earthquake-induced hazards prediction. In addition, seismic zonation for site classification according to the spatial distribution of the site period was also performed to determine the site amplification coefficients for seismic design and seismic performance evaluation at any site in the study area. Based on this case study on seismic zonations in Daejeon, it was verified that the GIS-based GTIS was very useful for the regional prediction of seismic hazards and also the decision support for seismic hazard mitigation.

Vegetation of Daecheong-bong. Mt. Seolag (설악산 대청봉의 식생)

  • Baek, Soon-Dal;Yang-Jai Yim
    • The Korean Journal of Ecology
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    • v.6 no.1
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    • pp.1-13
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    • 1983
  • A survey was conducted on the vegetation of southern slope of Daecheong-bong, Mt. Seolag, Located at the northern part of Taebaek mountain chain in the Central Korea. The altitudinal zonation of the vegetation was analyzed by distribution pattern of dominant species along thermal gradient, In additiion to these procedure th plant sociological studies by Braun-Blanquet(1964) were carried out. It was recognized that the vegetation is consist of 16 associations including Quercus mongolica-Lindera obtusiloba. association and the forest zone is classified into southern, central and northern part of cool temperate forest and subarctic forest.

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Spatial Distribution and Community Structure of Macrobenthos on the Sandy Shore of Anmyeondo, Korea (안면도 사질 조간대에 서식하는 대형저서동물의 공간분포 및 군집구조)

  • Jung, Yun-Hwan;Yoon, Kon-Tak;Park, Heung-Sik;Ma, Chae-Woo
    • Ocean and Polar Research
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    • v.35 no.1
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    • pp.27-37
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    • 2013
  • The western coast of Anmyeondo is open toward the Yellow sea and the northern and southern coasts are sandy and have simple coastlines. In this study, we investigated the spatial distribution and community structure of the macrobenthos that inhabit the sandy shore of Anmyeondo. For the study, we chose 8 sites encompassing 44 stations. In total, we have recorded 62 species, and collected 747 inds./$m^2$ on average. Zonation pattern did not appear because the mean grain size and organic contents of the study sites were similar among the macrobenthos. Polychaetes were most frequently recorded, but amphipods appeared in higher mean density. Macrobenthic community is classified into 3 groups largely based on the density difference among the dominant species and the groups were not influenced by environmental factors. The aggregated distribution of macrobenthos did not show a clear regional spatial difference but exhibited classification pattern emphasizing the density difference of the dominant species. The sandy shores of Anmyeondo are relatively more influenced by waves compared to other regions and the sediment moves more due to strong winds, etc. at low tide. We presume that the movement of sediment resulted in a relatively even sedimentary environment and consequently weakened environmental variables that change with the tide level. We concluded that the macrobenthic community does not show the zonation pattern in the sandy shores of Anmyeondo due to such influences.

Geology and Mineralization in Trapiche Cu-Mo Deposit, Apurimac State in Southeastern Peru (페루 남동부 아뿌리막주 트라피체 동-몰리브데늄 광상의 지질 및 광화작용)

  • Yang, Seok-Jun;Heo, Chul-Ho;Kim, You-Dong
    • Economic and Environmental Geology
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    • v.48 no.6
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    • pp.525-536
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    • 2015
  • Trapiche project corresponds to the advanced exploration stage which is thought to be a part of various porphyry copper deposits occurring in the margin of Andahuyalas-Yauri metallogenic belt. This deposit is genetically related to the monzonitic porphyry intrusion and Oligocene breccia pipe. Mineralization consists of primary sulfides such as pyrite, chalcopyrite, bornite, and molybdenite and secondary sulfides such as chalcocite, covellite and digenite. It occurs malachite, tenorite and cuprite as copper oxide. As a result of lixiviation or enrichment process, mineralization shows untypical zonation structure. Breccia and porphyry areas characterize the vertical zonation patterns. In the northern area, lixiviation zone, secondary enrichment zone, transitional zone and primary mineralized zone are distributed in northern area. In the western area of deposit, oxidation zone and mixed zones are narrowly occurred. Inferred resources of deposit is estimated to be 920 Mt @ 0.41% Cu with the cut-off grade of 0.15%.

Chemical Characterization of Oscillatory Zoned Tourmaline from Diaspore Nodule, an Aluminum-rich Clay Deposit, Milyang, South Korea (밀양 고알루미나 점토광상 다이아스포아 단괴내의 진동누대 전기석의 화학적 특징)

  • Choo, Chang-Oh;Kim, Yeong-Kyoo
    • Journal of the Mineralogical Society of Korea
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    • v.18 no.3 s.45
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    • pp.227-236
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    • 2005
  • Hydrothermal tourmaline occurs as aggregates or dissemination in the diaspore nodule from an aluminum-rich clay deposit, Milyang, southeastern Korea. Most crystals of tourmaline show complex textures that are finely zoned. The fine-scale chemical zonation of hydrothermal tourmaline reflects the fluctuation conditions that would be expected from fluid mixing in open systems. Oscillatory chemical zoning in tourmaline formed and showed similar patterns, regardless of its crystallographic directions. Mg was enriched in the early stage of crystal growth while Fe was enriched in the later stage, with fluctuations of the ratio of Fe to Mg. Chemical analysis, BSE images, and X-ray compositional maps confirm that the oscillatory Boning in tourmaline is exclusively controlled by the variations of Fe and Mg contents, but the contribution of boron to the zonation is insignificant. The fact that tourmaline altered to diaspore and dickite indicates that tourmaline was unstable with respect to these aluminous minerals as the B, Fe, and Mg activities decreased. Therefore, the aluminum activity may control the stability of tourmaline in the hydrothermal system.