A study on potential of liquefaction of sediments in Astaneh Ashrafieh using microscopic and dynamic properties and its effect on the sustainability of the city and the urban crisis

Study of natural hazards can be a useful tool in decision-making, planning and prioritization of measures to manage the crisis. In this research, the details of this approach in Astaneh Ashrafieh district in northern Iran in Gilan Province were evaluated and described given the history of liquefaction in the earthquake in Rudbar and Manjil in 1990. According to GSI maps of Sefidrud delta sediments in which Astaneh Ashrafieh area is located, the area from Paykouh to the beach mostly belongs to the Quaternary. At the delta level, there are three stratigraphic units related to the Pleistocene and five units related to the Holocene. In this study, more than 50 boreholes were drilled and a borehole for analysis was analyzed at the most critical parts of the region. Type of drilling in the study was machine-rotating and continuous sampling was conducted to a depth of 18 meters at a depth. Underground water level for this purpose was 3 meters and using experiments, research work began on the sand of the area, sand of the area was tested by field and laboratory studies such as on-site testing, grading test, and chemical and mineralogical tests. Based on the tests, sediments were mainly made of plagioclase, clinopyroxene and epidote minerals, a little quartz and carbonate debris and contained circular and semi-circular particulars and a small amount of clay and in some areas, silt in the surface layers.