Coastal hazards mapping using high-resolution UAV image and DEM. A Case study in Siung Beach, Gunungkidul, Indonesia

Abstract The southern coast of Gunungkidul, which is adjacent to the subduction zone, prone various coastal hazards. increasing number visitors beach leads more exposure and increases risks. This study aims determine hazards in Siung Beach, Yogyakarta. A high-resolution aerial image DEM were acquired using a low-cost Unmanned Aerial Vehicle. images processed Structure from Motion (SfM) photogrammetry generate an orthomosaic with 5cm spatial resolution. worst-case tsunami hazard scenario (12 m) was executed raster filtering on generated UAV-DEM. Based inundation model, most buildings are affected by scenario. According interpretation, rip current also spotted eastern part beach. considered channel rip, stationary bathymetric condition. Potential rockfall due slope instability might be occurred beach, as former enormous mass movement can delineated image. Beach formed combination volcanic origin karst process, resulting undulating topography. Due disaster management planning should established reduce