ارزیابی اثرات ناشی از عوامل آنتروپوژنیک و تکتونیک بر تحولات لندفرمی با هدف آمایش محیط (مطالعه موردی: رودخانه شور و دشت اشتهارد)

     توجه به اصول برنامه ریزی در نواحی شهری و روستایی با درنظر داشتن عناصرطبیعی محیط می‌تواند به تعادل و پایداری محیط و بهره‌برداری صحیح از منابع طبیعی منتهی شود. عواملی از قبیل تغییرات آب و هوایی، ویژگی های زمین شناسی، تکتونیک فعال و فعالیت های انسانی موجب تغییر در ویژگی های هندسی رودخانه، فرسایش و ناپایداری آن می شود که پیامدهایی از قبیل افزایش فرسایش و خشکی منطقه، تخریب خاک، آلودگی آب و هوا و ... را به دنبال دارد. در این پژوهش هدف بررسی تاثیرگذاری دخالت های انسانی و فعالیت های نئوتکتونیک بر ژئومورفولوژی رودخانه شور و دشت اشتهارد است. رودخانه شور در دشت اشتهارد جاری است و انتهای آن به دریاچه نمک قم می ریزد. روش اصلی کار مقایسه زمانی و مکانی تغییرات رودخانه و دشت اشتهارد است. ابزارهای پژوهش را تصاویر ماهواره ای لندست8 و لندست9 مربوط به سال های 2015 تا 2022، تصاویر سنتینل2، تصاویر تاریخی گوگل ارث و مدل رقومی ارتفاعی (dem) و نیز نقشه های زمین شناسی اشتهارد و ساوه تشکیل می دهد. تفسیر و تحلیل نتایج از طریق مقایسه تصاویر ماهواره ای و شواهد میدانی و مطالعات انجام شده درگذشته انجام گردید. نتایج حاصل از پژوهش نشان می دهد که عوامل آنتروپوژنیک با تغییر کاربری اراضی، استخراج از معادن، جاده سازی و تغییر مسیر اصلی آبراهه ها در کوتاه مدت بیشترین تاثیر را در تغییرات خصوصیات ژئومورفولوژیکی رودخانه و دشت اشتهارد داشته و شواهد تکتونیکی مانند بالاآمدگی ناشی از فعالیت گسل، تغییر مسیر آبراهه ها، جابه جایی مخروط افکنه ها در درازمدت مورفولوژی فعلی منطقه را شکل داده اند. 

evaluating the effects of anthropogenic and tectonic factors on landform changes with the aim of improving the environment (case study: shour river and eshtehard plain)

1- introductiontectonic and human activities, such as land-use changes and urbanization, have directly and indirectly impacted the geomorphic characteristics of landforms. these activities have influenced erosion and sedimentation rates, evaporation and transpiration processes, runoff patterns, river dynamics, and the frequency of mass movements. this study examines the effects of human and neotectonic activities on geomorphological dynamics of the shour river and eshtehard plain. the research aims to (1) assess geomorphological changes in landforms to identify potential negative consequences and regional instabilities and (2) to identify key factors driving these changes, evaluate their impacts, and determine the most significant contributors to environmental vulnerability. temporal and spatial changes in landforms were analyzed using aerial photographs, maps, and satellite images, supplemented with field data and observations. the findings were derived by cross-referencing satellite data, fieldwork results, and previous studies. information sources included documentary references, scholarly articles, library materials, satellite imagery, and geological maps. field observations were conducted across different seasons to assess the region’s response to tectonic and human influences.2- results human activities are a key driver of geomorphological changes in the shour river system. civil construction, road building along waterways and alluvial fans, and the establishment of factories and mines in the erodible formations of the eshtehard plain have increased erosion, sedimentation, and river channel displacement. land uses, such as agricultural fields, abandoned lands, salt marshes, pastures, and urban areas, were identified through satellite imagery, land-use maps, and field observations. the region’s geology and neotectonic activities also significantly influence geomorphological changes. rivers are sensitive to tectonic displacements, which can alter their longitudinal profiles and geomorphic characteristics. the longitudinal profile of the shour river is generally concave but shows convexities and fractures in some sections, often coinciding with intersections of the river and fault lines. these features suggest variations in the riverbed’s erodibility or elevation due to fault displacements. agricultural land in the region has declined due to water scarcity, while urban and industrial zones have expanded. population growth, increased groundwater extraction, reduced rainfall, higher temperatures, and rising evaporation rates have intensified drought conditions. many farmers have abandoned their land, leading to reduced agricultural activity. geological maps and tectonic analyses, combined with comparisons of historical google earth imagery, reveal that changes in river slopes and tributary deviations are likely linked to the eshtehard fault line and ongoing neotectonic activity.3- discussion & conclusionsthis study analyzed the impact of human and neotectonic activities on the shour river basin and the eshtehard plain. human activities, such as road construction, urban and rural development, industrial expansion, and waterway diversion, have disrupted erosion and sedimentation processes. mining activities have caused significant land-use changes, contributing to water and soil pollution, environmental degradation, and sedimentation in floodplains.tectonic activities have reshaped landforms by altering river courses intersecting with fault lines, displacing alluvial fans, and redirecting river flows. evidence from base-level changes, sequences of alluvial fans, and terraces in the region confirms the influence of neotectonic processes. the downstream sequence of alluvial fans near the halghedar heights suggests tectonic activity and shifts in base levels. channel displacement over time is also linked to fault-induced changes and base-level variations.in summary, human activities have had the greatest short-term impact on the shour river and eshtehard plain, while neotectonic processes have played a dominant role in shaping the region’s long-term geomorphology.