Progressive ground collapse in Central Aceh reaches 3 ha (7.4 acres), moves closer to homes and strategic infrastructure
A large ground collapse in Pondok Balik Village, Ketol District, Aceh Tengah Regency, Indonesia, has expanded to approximately 3 ha (7.4 acres). Monitoring data from the Aceh Energy and Mineral Resources Office (ESDM Aceh) show the affected area has grown from about 2.8 ha (6.9 acres) in 2022 and has now reached the main road corridor. Field reports indicate the active scarp continues to move toward farmland and residential areas located roughly 300–400 m (984–1 312 feet) away.
Image credit: Executive Vice President Gregorius Adi Trianto, Corporate Communications and TJSL PLN
Ground movement in Pondok Balik Village, Ketol District, Aceh Tengah Regency, Indonesia, now covers about 3 ha (7.4 acres) and continues to expand toward homes, farmland, and strategic infrastructure. The active edge lies roughly 300–400 m (984–1 312 feet) from residential areas, as of February 16, 2026. The collapse has enlarged progressively over more than two decades and remains active.
Cracks and shallow depressions were first noticed in the early 2000s, developing into visible ground fractures by 2004. By 2006, the movement had disrupted parts of a local transport route, prompting formal geological monitoring to begin in 2011.
Since then, the Aceh Energy and Mineral Resources Office, known as ESDM Aceh, has periodically measured the affected area.
According to the ESDM Aceh investigation letter dated January 27, 2026, repeated landslides have occurred in Pondok Balik since 2011. An earlier report submitted to the Regent of Central Aceh on May 30, 2022, recorded ground deformation covering about 2.8 ha (6.9 acres). The January 2026 document confirms expansion to approximately 3 ha (7.4 acres), with movement now reaching the main roadway and trending further southeast.
Post-disaster investigations referenced in the January 27 letter were conducted in four districts: Ketol, Kebayakan, Lut Tawar, and Bintang. The focus was to determine the causes of ground movement that led to landslides and the formation of the large ground depression in Pondok Balik.
Investigations determined that the slope is composed mainly of tuff and sandy volcanic rock from the Geureudong Formation, which weathers rapidly and loses strength when saturated. Continuous subsurface water flow further erodes the area, progressively weakening the slope’s internal structure.
Water-saturated zones were detected beneath the surface along the landslide’s movement path. Aerial imagery indicates that the mass is moving mainly toward the southeast, with additional displacement to the south, and the study anticipates further expansion along those directions.
The steep slope gradient further decreases stability, and investigators note that intense rainfall or seismic activity can trigger renewed movement and additional landslides.
The investigation specifically identifies Extra High Voltage Overhead Transmission Line towers, known as SUTET, along the expected movement path. PT PLN relocated sections of the 150 kV Bireuen to Takengon transmission corridor after the collapse approached tower foundations. Emergency support structures were installed to reduce the risk of power disruption.
The Ministry of Public Works plans to stabilize the area by injecting grout into underground cavities, redirecting river and surface water away from the unstable slope, sealing nearby wet caves that feed subsurface flow, and reinforcing soil along the road corridor. Approximately 400 m (1 312 feet) of the main road is considered at risk, and a 5.2 km (3.2 mile) alternative route would be used if the section becomes impassable.
The Regent of Central Aceh stated that the affected area is a center of community plantations, particularly chili cultivation. He warned that further widening could damage farmland in addition to infrastructure.
ESDM Aceh recommends that residents avoid landslide-prone areas, including the affected road.
References:
1 ESDM Aceh Beberkan Faktor Geologi Penyebab Sinkhole di Ketol, Aceh Tengah – Nukilan – February 2, 2026
2 Menteri PU Dody Hanggodo Tinjau Sinkhole Raksasa di Aceh Tengah : “Akan Kita Kerjakan Segera” – Humas Aceh Tengah – February 2, 2026
I’m a science journalist and researcher at The Watchers, contributing to the Epicenter edition, where I cover peer-reviewed scientific research and emerging discoveries across Earth and space sciences. With a background in astronomy and a passion for environmental science, I’ve worked in shark and coral conservation in Fiji, conducting reef and shark-behavior research, contributing to mangrove restoration, and earning PADI Open Water and Coral Reef Certifications. I bring a blend of scientific rigor and storytelling to illuminate the discoveries shaping our planet and beyond.
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