Mystery of flames in Seyegan, Sleman resolved as experts discover methane from ancient swamp
The mystery of flames appearing at a house in Mriyan, Margoagung, Seyegan District, Sleman Regency, has begun to clear up. A joint team of experts from UPN ‘Veteran’ Yogyakarta and Gadjah Mada University (UGM) has conducted in-depth investigations to uncover the scientific cause behind the alarming incident.
Preliminary research indicates that the flames were triggered by methane gas (CH4) escaping through building pores. Prof. Basuki Rahmad, Dean of the Faculty of Mineral and Energy Technology at UPN ‘Veteran’ Yogyakarta, explained on Saturday (30 May 2026) that the gas is likely sourced from ancient swamp deposits buried beneath the residential area.
“We conducted investigations to find the fire’s cause. The indication is gas beneath the surface. This area was once a swamp before being converted into residential housing,” Prof. Basuki stated in a statement received on Monday (1 June 2026).
This theory is supported by findings of siltstone outcrops at the site, characteristic of swamp geological formations. Researchers also observed air bubbles during tests at the bottom of the Nepen River, approximately 300 metres from the affected house.
Analysis by UPN’s FTME team shows that gas accumulated in underground rock layers has become saturated, then moved seeking release pathways to the surface.
“We found indications of a fault or crack running northward, directly towards the house. This is likely the channel through which methane migrated and surfaced,” Prof. Basuki added, noting the gas pressure is currently relatively weak.
Dr. Sarju Winardi from UGM’s Engineering Faculty stated his team is conducting field mapping and collecting data on pipework and sewage systems. Further steps include laboratory sampling to confirm the cause definitively.
As a preventive measure against dangerous gas accumulation, experts have issued two key recommendations for residents and nearby communities.
Sleman Regent Harda Kiswaya praised the academics’ swift assistance in the investigation, hoping collaboration between government, police, Gegana teams, and academics will provide scientific certainty to restore public calm.