نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه زمین‌شناسی معدنی و آب، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران
2 گروه زمین‌شناسی معدنی و آب، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران.
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The Varamin plain, located southeast of Tehran, is experiencing land subsidence, leading to infrastructure damage and reduced aquifer storage capacity. Despite previous zonation studies, the temporal dynamics of subsidence and its differential behavior across various geological units have received less attention. In this study, using 10-year time series (2014–2024) derived from radar interferometry (Sentinel‑1, LiCSBAS) and ARIMA modeling on stationary data (first‑order differencing), the autocorrelation structure of nine observation wells in different parts of the Varamin aquifer was analyzed. The results showed that in stations located within fine‑grained clay units (e.g., W-14 and W-03), the mean 10‑year cumulative subsidence rates were 726 mm and 473 mm, respectively, and the temporal behavior followed an autoregressive (AR) model with a stable trend. In contrast, stations in coarse‑grained units (W-06 and W-08) exhibited mean subsidence rates of less than 200 mm and showed purely random (moving average) behavior without a significant trend. The Ljung–Box test confirmed the adequacy of the models (p‑value > 0.05). The main finding of this study is that sediment grain size, particularly the thickness and continuity of clay layers, plays a decisive role in the type of subsidence dynamics (trending vs. random), and that groundwater level decline alone, without sufficient clay layers, does not lead to significant subsidence. This result highlights the need for risk zoning based on sediment type, not only on subsidence rates, in the management of alluvial aquifers.
کلیدواژه‌ها [English]
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