At Merapi volcano, lava dome failure may generate pyroclastic flow and threaten populations who live on its flanks. Here, we assessed the potential hazard of the Merapi lava dome by using drone photogrammetry and numerical modeling. Results show a weak structural depression that is associated with high thermal imaging in the southern Merapi lava dome sector. The southern lava dome sector may be further destabilized by typical rainfall at the Merapi summit and produce pyroclastic flow up to 4 km.