Aceh Giant Hole: BRIN Says Not a Sinkhole, But Landslide

Landslide, Not Sinkhole, Caused Large Hole in Central Aceh, Indonesia

Ketol, Central Aceh, Indonesia – A massive hole that appeared in a village in Central Aceh Regency, Aceh province, is the result of a landslide, not a sinkhole, Indonesia’s National Research and Innovation Agency (BRIN) clarified on Saturday, February 21, 2026.

The landslide, spanning more than 30,000 square meters, has disrupted access between subdistricts and submerged residents’ plantations. Initial reports had led to speculation about a sinkhole, but BRIN’s assessment points to a different geological process.

“What happened in Central Aceh was actually a landslide phenomenon, not a sinkhole,” said Adrin Tohari, head of BRIN’s Geological Disaster Research Center, in a statement. “The tuff layer is not dense and its strength is low, so We see easy to erode and collapse.”

According to BRIN, the area is composed of tuff, a material resulting from volcanic activity from Mount Geurendong, an inactive volcano. This tuff layer, being relatively young and not fully consolidated, is particularly susceptible to erosion and collapse.

Analysis of satellite imagery from Google Earth dating back to 2010 reveals the presence of a small valley in the area. Over time, erosion and landslide processes have gradually widened and lengthened this valley, ultimately forming the large hole visible today.

BRIN researchers also suspect that a 6.2 magnitude earthquake that struck Central Aceh in 2013 may have contributed to the instability of the slope, accelerating the landslide process. The quake likely weakened the structural integrity of the hillside.

Heavy rainfall is identified as a primary trigger for the landslide. The porous nature of the tuff rock allows it to easily become saturated with water, reducing its binding power and leading to collapse. The steep slope, already compromised by previous landslide activity, further exacerbates the situation.

Water from nearby plantation irrigation canals is also believed to have played a role. The rapid flow and seepage of water into the ground increases the moisture content of the tuff layer, increasing the risk of collapse. “If the irrigation channels are open and water continues to enter the ground, the already fragile layer becomes increasingly unstable,” Tohari explained.

BRIN hypothesizes that groundwater flow at the boundary between a denser lava flow layer and the fragile tuff rock above may also be contributing to erosion at the base of the slope, causing the upper portion of the cliff to lose support and collapse gradually. The agency emphasizes that Here’s not a sudden event, but a process that has unfolded over decades, potentially even centuries.

BRIN noted that similar geological formations and phenomena can be observed in other regions with volcanic rock formations, citing Ngarai Sianok in West Sumatra as an example. The agency has not yet conducted on-site research but has based its analysis on satellite imagery and publicly available data.

BRIN recommends updating existing landslide vulnerability maps in light of this event to improve accuracy and operational effectiveness. They also urge residents to be vigilant for early warning signs, such as cracks in the ground or minor ground subsidence.

“Peta kerentanan gerakan tanah sebenarnya sudah ada, tetapi perlu diperbarui setelah kejadian ini agar lebih akurat dan operasional. Yang terpenting sekarang adalah memahami prosesnya dan segera melakukan langkah mitigasi agar risiko korban jiwa dapat dihindari,” Tohari stated.