پهنه‌بندی عرصه‌های آسیب‌پذیر در برابر مخاطرات طبیعی با تاکید بر زمین لغزش (مطالعه‌ موردی: زیرحوضه گرگانرود شهرستان گرگان )

حرکات توده‌ای، ازجمله پدیده‌های مورفودینامیک هستند که تحت تاثیر عوامل مختلفی در سطح دامنه‌های مناطق کوهستانی به وقوع می‌پیوندد پهنه‌بندی لغزش‌ها یکی از روش‌هایی است که می‌توان به کمک آن مناطق بحرانی را تعیین کرده و از نقشه‌های پهنه‌بندی به‌دست‌آمده در برنامه‌ریزی‌ها استفاده کرد در این راستا با توجه به موضوع هدف پژوهش حاضر بررسی عرصه‌های آسیب‌پذیر در برابر مخاطرات طبیعی با تاکید بر زمین‌لغزش است. تحقیق حاضر، با توجه به ماهیت مسئله و موضوع موردبررسی، از نوع توصیفی تحلیلی و از حیث مطالعات کاربردی با تاکید بر روش‌های کمی است. جهت شناسایی مکان‌های دارای پتانسیل لغزش بالا معیارهایی از قبیل: (شیب، جهت شیب، کاربری اراضی، فاصله از مراکز سکونتی، انحنای زمین، بارش، ارتفاع، تراکم پوشش گیاهی، زمین‌شناسی، خاک، تراکم آبراهه، فاصله از جاده مورد ملاحظه قرارگرفته‌اند به‌منظور محاسبه تراکم و میزان سبزی پوشش گیاهی از باندهای مادون‌قرمز نزدیک و باند قرمز(45) ماهواره لندست8 استفاده گردید و خروجی نهایی با روش هم‌پوشانی حسابی در محیط gisمحاسبه شد تمامی فرایندها و تجزیه تحلیل داده‌ها در محیط gis و نرم‌افزار super decision استفاده گردید همچنین نتایج بدست آمده در نقشه نهایی نشان‌دهنده آن است که طبقه 5 با ضریب رانش بالا 15 درصد از کل مساحت منطقه، طبقه4 با ضریب لغزش زیاد 19 درصد، طبقه3 با ضریب متوسط35 درصد، طبقه 2 با ضریب کم22 درصد، طبقه1 با ضریب خیلی کم8 درصد را به خود اختصاص داده‌اند درنتیجه بالغ‌بر 34 درصد از کل منطقه در معرض لغزش شدید قرار دارد.

The Zoning of Vulnerable Areas Against Natural Hazards with an Landslide(Case Study: Gorganroud Subdomain In Gorgan City)

Introduction Mass movements are among the morphodynamic phenomena that occur under the influence of various factors at the level of the mountain range. The zoning of landslides is one of the methods that can be used to help those regions Determined the critical situation and used the mapping maps obtained in the planning, the slopes of the movement included the granular and massive movements of the earth, which, in the region, have several natural causes And human beings can interfere in its occurrence, which unfortunately causes some serious financial and psychological damage. Many landslides are quite natural because of copper So large or even small changes can cause landslides. In landslide, the landslide flows downwards. The flow of soil and flowers in the thrust of the ground is quite moldy and occurs where fine grained soil is completely damaged and saturated with water and flows down the sloping surface, although The thrust of the ground can be slow, but it usually has a terrible speed and most of them are fast and very dangerous.Methods and materialThe present study is descriptiveanalytic with regard to the nature of the problem and the subject matter and is a type of applied studies with an emphasis on quantitative methods. The purpose of this study is to investigate the areas of vulnerable natural hazards with emphasis on landslide ( (Gorganroud subregion) is used to identify areas with high thrust potential such as: slope, gradient direction, land use, distance from residential centers, land curvature, precipitation, elevation, vegetation density, geology, Soil, water condensation, distance from the road have been considered in order to calculate the density and vegetation cover vegetation of infrared bands The Landsat 8 satellite was used for the red light (45) and the final output was calculated using an integrated approach in the GIS environment. All the processes and data analysis in the GIS environment and Super decision software were used, so that each weight Following the criteria of the main criterion in the superconducting software environment, Sepeh was multiplied by using the weighted and linear overlapping methods of each of the sub criteria of the main criteria in their weights, and ultimately by the overlapping of each of the overlapping criteria in The main criterion weight of the multiplication and the final output was determined in the form of a thrust map in 5 floors.Results and discussion In order to measure the impact of effective factors on landslide, the analytical software mentioned in the research methodology has been used and also to determine the effective indexes in determining low and high risk areas for identifying the degree of drift and land valuation for Types of activities and the importance of each of these criteria in relation to each other according to the current status and the information gathered, as well as the study of books, previous plans and experts’ opinion has been taken that ultimately in the form of a layer The information system enters the GIS environment at a later stage, into proportional weights of intelligence layers The importance and the impact of these are given in the appropriate field selection. In order to achieve these indicators, a series of maps and databases were needed that were prepared in the GIS environment and prepared after In order to analyze these maps we used linear and linear overlapping methods.Discussion and conclusionAccordingly, according to the valuation of each of the criteria above, the main criterion for topography is the highest value in the curvilinear drift with the weight of 0.564323 and in the hydrographic criterion the greatest interference is in the land of the river density zone with a weight of 0.833333 and in the facility standard Substructure of distance from the road with a weight of 0.800000 and in the criterion of utilization and vegetation density, the criterion of density of vegetation with the weight of 0.50000 and also in the ground and soil criterion are the geological layer with the weight of 833333 respectively, respectively, also have the highest value. The area obtained in the final map of the 5th floor with a high runoff factor of 15% of the total area of the area, 4th floor with a drift coefficient 19%, 3rd floor with a mean of 35%, 2nd floor with a low coefficient of 22%, 1st floor with a very low coefficient of 8%, resulting in up to 34% of the total area exposed to extreme poverty.Keywords: Slide, Slip, Gorganroud, Gorgan, Super decision, GIS.