Spatio-Temporal Analysis of Susceptibility Hazardous and Risk Mapping in Post-2023 Simangulampe Devastating Flood

Abstract Over 169 people along the Simangulampe upstream were under devastating flood and worst landslide watches in December 2023 due to a significant storm bringing the heaviest rainfall and moving giant boulders. Indeed, there are far fewer studies and information on susceptibility hazards in Simangalumpe than in others. First-rate information on impressive risk mitigation strategies increased climate-change consideration and reduced flood risk. We adopt C-band synthetic aperture radar and multispectral imagery from Sentinel to identify, visualize, and analyze flash flood mapping and mitigating to address this issue. Precisely, Simangalumpe flood is considered from surface water indices with various parameters: Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI), and SAR flood inundation mapping. Results show low NDVI values- over 50 percent of plant canopies are damaged (uprooted and broken trees) along Simangulampe upstream. Combining multispectral and SAR properties of the surface water index shows the surface extent of water bodies in Simagalumpe upstream and covers giant boulders. Finally, developing spatial and temporal analysis from multispectral and SAR data results in information on mitigating flash flooding and reducing unnecessary threats.