بررسي خطر زمين‌لغزش به روش AHP در ساحل درياي خزر، محدودة نوشهر تا رامسر

Landslide hazard assessment by AHP along Caspian sea coast Nowshahr-Ramsar

بر اساس بررسي­هاي صحرايي، اين منطقه از لحاظ وقوع زمين­ لغزش داراي پتانسيل بالايي مي­باشد و در سرتاسر منطقه مي­توان انواع مختلف حركات دامنه­اي را مشاهده نمود. در اين مقاله داده‌هاي ورودي در مدل AHP جهت تحليل خطر زمين­ لغزش شامل عوامل شيب، زمين­ شناسي، گسل، آبراهه، جهت شيب، ارتفاع، كاربري اراضي و راه­هاي دسترسي مي‌باشند كه با استفاده از نرم­افزار ArcGIS رقومي گشته و به صورت لايه‌هاي اطلاعاتي ذخيره شده­اند. نقشه­ تهيه شده با استفاده از روش فاصله برابر در 5 رده خطر خيلي‌كم، كم، متوسط، زياد و خيلي‌زياد طبقه‌بندي شده است. بررسي نتايج نشان مي­دهد عوامل ليتولوژي، شيب و گسل از جمله مهم­ترين عوامل مؤثر در وقوع زمين­ لغزش در اين منطقه هستند و بيش از 30 درصد از اراضي منطقه در رده خطر بالا قرار دارد.

The purpose of this study is to investigate the landslide hazard in a coastal area of Caspian Sea elongated from Nowshahr to Ramsar. High population density and lack of plains, as well as increased constructions and architectural and agricultural activities on slopes highlight the necessity of such studies in this area. Landslide distribution map for the area was achieved through field studies. According to these studies, this area has a high potential for landslide incidence, and various kinds of Mass wasting can be observed across the area. To analyze landslide hazard in the area, we considered such factors as slope, geology, fault, river, slope aspect, elevation, land use, access routes and shear resistance as effective factors in landslide incidence. Data were digitalized using ArcGIS software and stored as information layers. To develop the Landslide hazard zoning map for the area, method of AHP have been used. The map then are classified into five hazard ranges of very low, low, moderate, high and very high. Evaluation of zoning map with regard to landslide density and stable points shows that obtained maps hold an acceptable validity. Results analysis shows that slope, geology and fault are among the most important factors involved in landslide incidence. Developed zoning map can be practical in engineering projects architectural activities in the investigated area.