Environmental Erosion Research

fa پهنه‌بندی پتانسیل خطر زمین‌لغزش در شهرستان خرم‌آباد Landslide risk zoning in Khorramabad County روشهای نوین و دقیق در تهیّه نقشه فرسایش (سنجش از دور و سیستم‌های اطلاعات جغرافیایی) مستخرج از پایان‌نامه / رساله / طرح پژوهشی زمین‌لغزش یکی از پدیده‌های طبیعی است که در تحول و فرسایش اشکال زمین مشارکت دارد. این پدیده زمانیکه جوامع انسانی را تحت تأثیر قرار می‌دهد، می‌تواند خسارات و تلفات فراوانی را درپی داشته باشد. با توجه به اهمیّت موضوع، کنترل و پهنه‌بندی خطر بالقوۀ زمین‌لغزش به‌عنوان یکی از انواع مخاطرات، در توسعۀ پایدار ضروری به نظر می‌رسد. شهرستان خرم‌آباد به‌دلیل قرارگیری در زون زاگرس چین‌خورده و داشتن خصوصیات زمین‌شناسی، فیزیوگرافی، انسانی و شرایط آب‌و‌هوایی مستعد بروز خطرات ناشی از پدیدۀ زمین‌لغزش است. لذا هدف از این تحقیق، شناسایی مهم‌ترین عوامل ایجاد زمین‌لغزش‌ها و پهنه‌بندی وقوع آن، در سطح شهرستان خرم‌آباد با استفاده از تکنیک چندمعیارۀ مارکوس می‌باشد. در راستای تحقق اهداف پژوهش، معیارهای ارتفاع، شیب، جهت شیب،  بارش، سازندهای زمین‌شناسی، فاصله از آبراهه، فاصله از جاده و کاربری  به‌عنوان متغیرهای مستقل انتخاب شد. نتایج مطالعه نشان داد که معیارهای شیب، لیتولوژی، کاربری اراضی و فاصله از شبکه راه‌ها، به‌ترتیب با ضرایب وزنی 158/0، 153/0، 131/0 و 117/0، به‌عنوان تأثیرگذارترین پارامترهای مؤثر بر زمین‌لغزش در محدوده شهرستان می‌باشند. با توجه به نقشۀ خطرپذیری زمین‌لغزش در شهرستان خرم‌آباد، 10/820 کیلومترمربع از منطقه در طبقۀ خطر بسیار زیاد، 04/1362کیلومترمربع در طبقۀ خطر زیاد و  33/1361 کیلومترمربع در طبقۀ متوسط قرار دارند که با توجه به طیف وسیع مناطق با احتمال بالای وقوع خطر، اجرای برنامه های مدیریت ریسک و پروژه‌های حفاظتی ضرورتی انکارناپذیر است. همچنین ارزیابی مقایسه‌ای توزیع فضایی نقاط زمین‌لغزش با نتایج پژوهش، به انطباق این نقاط با پهنه‌های پرخطر و بسیار پرخطر اشاره دارد. نتایج تحلیل منحنی ROC برای روش مارکوس نیز نشان داد که نقشۀ حساسیت زمین‌لغزش تهیه شده در منطقه موردمطالعه با سطح زیر منحنی (92/0AUC) دارای قدرت پیش‌بینی عالی است.   1- Introduction Slope movements are among the geomorphological and geological hazards that play a very effective role in changing the shape of the earth's surface (Jafari and Timajani, 2024:188). Landslides, as a type of slope movements, refer to the downward movement of a mass of rock, debris, and soil on a slope under the influence of gravity (Silakhouri et al., 2023:123; Singh et al., 2024:1). Landslides can have significant socio-economic and environmental impacts and lead to casualties, injuries, and damage to property and infrastructure (Gilanipour et al., 2025:1404). Given the importance of the issue, controlling and zoning the potential risk of landslides as one of the types of hazards seems essential in sustainable development. Khorramabad County is prone to landslide hazards due to its location in the folded Zagor zone and geological characteristics such as lithology, physiographic, climatic, and human conditions. Given the importance of the issue, it seems essential to examine the effect of each criterion and appropriately estimate the risk of the county to landslide hazards. Therefore, in this study, zoning of Khorramabad County against landslide hazards has been considered using the new MARCOS multi-criteria algorithm. 2-Methodology The present study, considering the nature of the problem and the subject under study, is of a research-applied type, and its research method is an analysis based on the integration of data analysis, geographic information systems, and the use of multi-criteria analysis techniques. Arc GIS, Idrisi, and Excel software were used for image processing and data analysis. Considering that landslides occur under the influence of several factors, identifying the factors effective in the occurrence of landslides is of great importance. First, after reviewing similar scientific research in the field of the subject, conducting field observations, and considering the natural and human conditions of the region, 9 factors of DEM, slope, aspect, geology, distance from the fault, land use, precipitation, distance from communication road, and distance from the river were identified as effective factors in creating landslide risk in Khorramabad County. In the next stage, information layers related to each factor were prepared in the geographic information system environment. The weighting of the factors studied was done according to the CRITIC method, and the final analysis was done using the MARCOS multi-criteria method. After preparing the landslide susceptibility map, the accuracy of the models was examined using the ROC curve. 3- Results According to the results of the study, 479.29 square kilometers of the city have very low potential, 971.24 square kilometers have low potential, and 1361.33 square kilometers have medium potential. The high-risk and very high-risk classes cover 1362.04 and 820.10 square kilometers of the city area, respectively. Matching the distribution of landslide points and areas at risk based on the zoning map obtained from the study shows that the largest number and percentage of landslide surfaces are located in the two very high-risk (44.44 percent of landslide points) and high-risk (42.22 percent of landslide points) classes. In addition, the medium-risk class also includes 14.44 percent of landslide areas, and in the two low-risk and very low-risk classes, the distribution of landslide points is not observed. A study of the distribution of urban and rural areas in the county also shows that the city of Biranshahr (Chaghlondi), along with 42.30 percent of the villages in the county, are in the very high-risk category. The cities of Khorramabad, Grab, and Zagheh, along with 34.03 percent of the villages, are in the high-risk category. The middle category includes the city of Sepiddasht and 17.65 percent of the villages in the county. The research findings also showed that the dominance of slopes with medium to steep slopes (10 to 50), altitudes of 1000 to 3000 meters, receiving abundant rainfall, diverse land uses (especially agricultural, forest cover, pastures), trenching and removal of the slopes' toes following road construction and development activities, susceptible geological formations (alternation of limestone, marl, shale, and sandstone layers), undercutting of the slope support by flowing waters, fault structures, and slope direction (especially; northern, western, northwest, eastern, and southeastern directions) have led to an increase in landslide potential at the county level. 4- Discussion & Conclusions Validation of the Marcus model using the ROC curve (with an area under the curve of 0.92%) indicates the excellent efficiency and accuracy of the model for preparing a landslide hazard map of the region. Therefore, given the appropriate accuracy of the MARCOS model, in order to save time and money, in order to zoning landslide susceptibility and identify areas at risk, it is recommended for other researchers to use this method. Finally, it should be noted that, given the large extent of landslide-prone areas in Khorramabad County, it is necessary that the results of this study be given serious attention by relevant organizations (such as the Crisis Management Organization, the General Administration of Natural Resources and Watershed Management, the General Administration of Roads and Urban Development, the Regional Water Organization, and other organizations related to environmental hazard issues) in order to introduce important criteria involved in the creation of landslides in the county and identify areas with a high probability of this hazard, in order to carry out protective, watershed management, and preventive and restorative management measures to reduce the risk of landslides and stabilize slopes.   مخاطره, حرکت دامنه‌ای, تحلیل‌چندمعیاره, خرم‌آباد. Risk, Slope movement, multi-criteria analysis, Khorramabad. 64 87 http://magazine.hormozgan.ac.ir/browse.php?a_code=A-10-93-9&slc_lang=fa&sid=1 Sayyad Asghari Saraskanroud صیاد اصغری سراسکانرود s.asghari@uma.ac.ir 100319475328460010134 100319475328460010134 Yes Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran دانشکده علوم اجتماعی، دانشگاه محقق اردبیلی، اردبیل، ایران Elnaz Piroozi الناز پبروزی e.pirouzi@uma.ac.ir 100319475328460010135 100319475328460010135 No Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran دانشکده علوم اجتماعی، دانشگاه محقق اردبیلی، اردبیل، ایران