Natural hazards including landslides, flash floods, earthquakes and hurricanes have been constituted a significant problem in many countries. Three study areas in Iran, Japan and Malaysia were selected to be study in the current research. One the most considerable natural hazards in the study areas is flood. This paper aims to map flooded areas in these regions by using synthetic aperture Radar (SAR) imagery of Sentinel-1 (for Iran and Malaysia) and ALOS-2 (for Japan), without using any automated classifier. A total number of two satellite imageries (before and right after the events) were collected for all three areas. Using Sentinel application platform (SNAP) software the images were corrected, stacked and combined in order to map flooded areas. Results indicate that this kind of flood mapping is precise, fast and easy to use. At the same time, using confusion matrix and ground control points (GCPs) the final maps was validated for two study areas of Iran and Malaysia; but, we did not have any GCPs for validating created map for Japan. This paper can be helpful to policy and decision makers in order to map flooded areas immediately, especially when we need a quick action for settling camps for evacuees during flooding days.
