WHAT IS HAZARD MAP?by Swesha Dhamala | 30-03-2020 15:17 |
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Any hazard map has its specific purpose. So, hazard mapping is guided by the following three principles: (i) Avoidance In the desk study, pre-field maps are prepared to show the causative factors in the study area with the help of aerial photographs, satellite imageries, topographic maps and geological maps. The pre-field maps thus prepared include slope-morphometry, relative relief, land-use and land-cover, lithology, structure, soil depth, soil type and hydro geological maps. This information helps systematic planning and excursion of field. During the field study, more detailed structural & lithological, soil-depth, soil type, hydrogeological maps are prepared. The details of pre-field maps prepared are verified in the field and modified if necessary. Field studies are carried out to collect the required data-facet to estimate the total hazards of the facet. For each spatial area, some eating has been assigned to each attribute whatever present within the area. The rating values for each map are calculated. After that, according to the superimposition methods, all these thematic maps are overlapped one by one giving their rating values to each map for hazard assessment. These values are added. Then the area is divided into low, medium and high hazard levels on the basis of final values. In this way, the hazard map can be prepared |