Seismic vulnerability hazard assessment of south coastal on the Caspian Sea

This research has directed to gain the seismic instability hazard assessment in the southern coastal provinces of the Caspian Sea as main target. Main active faults have been recognized by correlation the seismic source points with faults location map. Mazandaran great fault, Alborz, Lahijan, Badeleh, Lavij and Astara was known as the most active faults during the Quaternary period. High vulnerable area has been distinguished by applying seismic occurrence probability with magnitude more than 5 Richter. Then geotechnical hazard degree has been evaluated by overlapping the other information layers such as: topography, slope and its direction, sediments composition, precipitation amount, roads and construction, land use and water table condition in the universal ranking model in the geographical information system. Data results as GIS maps show that the seismic hazard risk is relatively high grade at near the main faults (Mazandaran great fault, Astara and Lahijan faults). The occurrence probability of land slide is concentrated near the centre part of the southern coasts of the Caspian Sea (Noor- Neka) and along the Gorgan plain with lose sediment.Other geotechnical hazard events such as: liquefaction and settlement are dominated along the east part and west part of the study area (Amirabad- Babolsar, Talesh, and Astara) with high concentration of sand sediment near the beach and rivers mouth.