Jakarta (ANTARA) – Indonesia's National Research and Innovation Agency (BRIN) clarified on Saturday that a large hole in a village in Central Aceh, Aceh, was caused by a landslide, not a sinkhole.”What happened in Central Aceh was actually a landslide, not a sinkhole. The tuff layer is not dense and has low strength, making it easily eroded and prone to collapse,” Adrin Tohari, head of BRIN's Geological Disaster Research Center, said in a statement.He said satellite imagery from 2010 had already shown a small valley or canyon at the site in Pondok Balik Village, Ketol Subdistrict. Over time, erosion and repeated landslides widened and deepened the area, forming the large cavity seen today.The Aceh Energy and Mineral Resources Agency estimated that the affected area spans more than 30,000 square meters, with a depth of up to 100 meters. Locals and media initially labeled it a “sinkhole.”Tohari also pointed to seismic activity as a contributing factor. The 6.2-magnitude earthquake that struck Central Aceh in 2013 likely weakened the slope structure and increased instability.Heavy rainfall further accelerated the process, as the fragile tuff rock became saturated easily, losing cohesion and collapsing. The steep slope gradient created by previous landslides worsened the condition.Surface water from plantation irrigation channels may have also contributed to the landslide by increasing water infiltration into the soil, Tohari added.”If irrigation channels remain open and water continues to seep into the ground, the already fragile layer will become even more unstable,” he said.Tohari explained that groundwater likely flows along the boundary between dense lava rock at the base of the cliff and the overlying tuff layer. Erosion at the slope's base can reduce support, leading to collapse of the upper section.He stressed that the phenomenon developed gradually over tens to hundreds of years, with earthquakes and rainfall acting as accelerating factors.Similar geological conditions are found in other regions with young volcanic rock formations, he noted.As an example, Tohari cited Sianok Canyon in West Sumatra, which formed through long-term geological processes linked to tectonic activity along the Great Sumatran Fault.”We are still analyzing the situation based on image data and public information. Comprehensive field research is needed to determine the detailed cause,” he said.He emphasized the need for mitigation measures, including controlling surface water flow, establishing hazard zones, and installing landslide early warning systems.Tohari also urged residents to watch for early warning signs such as ground cracks or minor subsidence.”Landslide vulnerability maps already exist, but they need to be updated following this incident to improve accuracy. The priority now is to understand the process and take immediate mitigation steps to prevent casualties,” he added.