ارزیابی وضعیت آسیب‌پذیری روستاهای مناطق کوهستانی در برابر مخاطرات طبیعی (مطالعه موردی: شهرستان‌های ایذه و اندیکا)

Earthquakes and landslides are among the most significant natural hazards worldwide, causing extensive damage to infrastructure, the environment, and human communities each year. Northern regions of Khuzestan Province are among the areas exposed to these hazards. Given the importance of the issue, this study aims to identify vulnerable areas to landslides and earthquakes in the counties of Izeh and Andika in Khuzestan Province. The main data sources used in this research include CHIRPS and MODIS satellite imagery, the 30-meter SRTM digital elevation model, and the 1:100,000 geological digital map of the region. The main tools employed were Google Earth Engine, ArcGIS, and IDRISI. In this study, a hybrid model combining the Weighted Linear Combination (WLC) and relative weight coefficients was used to assess the vulnerability of the villages in the region to landslides and earthquakes. According to the results, 85.3% of the villages in the area have a high vulnerability to earthquakes, and 9.7% to landslides. Additionally, about 9% of the villages are simultaneously threatened by both hazards. This highlights the urgent need for special attention to rural infrastructure and risk-based planning in these areas. The findings also indicate that Andika County has a higher density of villages vulnerable to both hazards. Based on the obtained results, it is recommended that comprehensive measures be taken to reduce vulnerability in the counties of Izeh and Andika, including the reinforcement of rural buildings using government facilities and public participation, the development and deployment of early warning systems, and the training of local residents in preparedness and crisis management.
 
Extended Abstract
 
Introduction
Iran, located within the seismically active Alpine-Himalayan belt, has a high seismic potential, which has placed many of its major cities at risk from this natural hazard (Ganjayan, 2024). Additionally, due to the fact that a large portion of its territory is covered by mountainous areas, it also has a high potential for landslides. One of the regions exposed to natural hazards such as earthquakes and landslides is the northern part of Khuzestan Province. The counties of Andika and Izeh, located in the northern part of Khuzestan, are mountainous areas with a high density of villages and a widespread distribution of human settlements along mountain slopes and riverbanks. Many of these villages are highly vulnerable to disasters such as earthquakes and landslides due to unregulated construction, lack of resilient infrastructure, and the absence of monitoring and early warning systems. This not only threatens the lives of residents but also causes irreparable damage to natural resources, agricultural lands, transportation routes, and water sources. Since sustainable rural development requires the identification and management of environmental risks, examining and analyzing areas prone to earthquakes and landslides especially in the rural areas of Andika and Izeh counties is an inevitable necessity. This study can assist local, provincial, and national authorities in prioritizing vulnerable areas and implementing more accurate planning for infrastructure reinforcement, public education, and disaster management. Given the importance of the issue, this research focuses on identifying vulnerable areas to landslide and earthquake hazards in the counties of Izeh and Andika in Khuzestan Province.
 
Methodology
In this study, satellite imagery from CHIRPS and MODIS, the 30-meter SRTM digital elevation model, and the 1:100,000 geological digital layer of the region were used as the main data sources. The primary tools employed in this research included Google Earth Engine, ArcGIS, and IDRISI. Additionally, a combined WLC model and relative weighting coefficients were utilized. Based on the subject and objectives, the study was conducted in two main phases. In the first phase, vulnerable areas to landslides and earthquakes were identified. To detect areas prone to landslides, eight parameters were used: elevation, slope, distance from rivers, distance from roads, lithology, distance from faults, vegetation density, and average annual precipitation. For identifying earthquake-vulnerable areas, the parameters included distance from earthquake epicenters, distance from faults, lithology, and slope. After preparing the relevant data layers, they were standardized and weighted. Once the weights were applied, the data layers were imported into TerrSet software and integrated using the Weighted Linear Combination (WLC) method to produce the final vulnerability maps for both landslides and earthquakes. In the second phase, hazard maps of Izeh and Andika counties were prepared, followed by an assessment of the vulnerability status of villages in these counties against landslide and earthquake hazards.
 
Results and Discussion
According to the findings, the landslide hazard maps indicate that the eastern and northeastern parts of Izeh and Andika counties have the highest potential for landslide occurrence. This is mainly due to the presence of steep slopes, high elevations, specific geological formations, and unique hydrological conditions in these areas. The combination of these factors contributes to slope instability and a high susceptibility to landslides. Regarding earthquakes, the results show that the western parts of Izeh County and large portions of Andika County fall within areas with a high vulnerability to seismic hazards. These regions are located near active faults, and their geological structures indicate a high potential for strong earthquakes. In particular, proximity to seismogenic faults and the lack of earthquake-resistant infrastructure are among the main factors exacerbating this vulnerability.
 
Conclusion
The findings of this study indicate that a large portion of Izeh and Andika counties—particularly the eastern, northeastern, and western regions—are exposed to natural hazards such as earthquakes and landslides. Spatial analysis using the WLC method and relative weighting coefficients revealed that 85.3% of the villages in the region have a high vulnerability to earthquakes, 9.7% are highly vulnerable to landslides, and about 9% are simultaneously threatened by both hazards. This underscores the urgent need for risk-based planning and greater attention to rural infrastructure in these areas. The combination of natural factors such as slope and elevation, along with human factors such as unregulated construction and poor resource management, has increased the risk level in these regions. Furthermore, it was found that Andika County has a higher concentration of villages vulnerable to both hazards. Overall, this study highlights the value of spatial analysis in identifying high-risk areas and prioritizing risk reduction efforts, offering valuable guidance to decision-makers. Based on the results, it is recommended to implement comprehensive measures to reduce vulnerability in Izeh and Andika counties, including reinforcement of rural buildings through government support and community participation, establishment of early warning systems, public education on preparedness and disaster management, restriction of development in high-risk zones, and the use of modern technologies for continuous monitoring of faults and unstable slopes. Integrating spatial data with development planning can also lead to more accurate and effective decision-making in reducing regional vulnerability.