RRI.CO.ID, Padang  - A sudden sinkhole that appeared in a rice field in Situjuah Batua Village, Limapuluh Kota Regency, West Sumatra, has attracted national attention due to its unusual geological characteristics and potential risks to public safety.

The massive ground collapse appeared on January 4, 2026, following a loud rumbling sound, and has continued to widen. According to the Geological Agency of the Ministry of Energy and Mineral Resources (ESDM), the phenomenon is considered rare because it did not form in limestone terrain, where sinkholes are typically found.

“Based on our rapid assessment, this sinkhole is geologically unique. The assessment, conducted between January 9 and 11, identified the sinkhole as a pseudo-karst phenomenon occurring in volcanic deposits rather than karst limestone," said Taufiq Wira Buana, an engineering geologist at the ESDM Geological Agency, on February 8, 2026, as quoted by  Antara.

Researchers found that an underground river had gradually carved a cavity within volcanic material known as tuffapilla. The process was driven by internal erosion, or piping, where water slowly removes soil particles from within, weakening the ground structure until it collapses.

Another striking feature is the presence of water filling the sinkhole, giving it a blue appearance similar to a cenote, a term usually associated with karst landscapes. Tests showed the water’s pH ranged from slightly acidic to neutral.

However, officials stressed that the sinkhole poses health and safety concerns. West Sumatra Deputy Governor Vasko Ruseimy confirmed that laboratory tests detected E. coli bacteria in the water, with acidity levels below the safe threshold of pH 6.5.

“The water quality shows a fairly high bacterial content. We strongly advise the public not to drink or use it,” Vasko said on February 2, 2026. 

Geologists concluded that the sinkhole was caused by two main factors: continuous water infiltration from rainfall and groundwater, and unstable volcanic soil that erodes easily. Existing ground cracks and changes in underground pressure further accelerated the collapse.

The provincial and regency administrations, together with the Geological Agency and health authorities, are continuing monitoring and in-depth studies to ensure the safety of nearby communities. 

The Deputy Governor expressed his hope that this explanation will serve as a guideline for local residents to avoid misusing water from the sinkhole. He emphasized that this phenomenon is purely a natural process and is not linked to mystical beliefs or claims of curing diseases.

"The water in the sinkhole cannot cure diseases. This is a natural geological process, nothing more,” Vasko stressed. ***