Geologists Uncover Source of Mysterious Fires at Seyegan Sleman Home

Geologists from UPN Veteran Yogyakarta and Gadjah Mada University have been investigating the cause of the mysterious fires at Mutfiana’s home in Seyegan, Sleman. Here are their findings.

It has been reported that Mutfiana’s house has caught fire 39 times between Saturday (24 May) and Thursday (28 May). The flames are suspected to originate from methane gas accumulating in the property.

UPN Jogja Geologist Reveals Gas Source

Prof. Dr. Ir. RM. Basuki Rahmad, Dean of the Faculty of Mineral and Energy Technology (FTME) at UPN Jogja, observed Mutfiana’s house. He stated that the methane gas in the property is suspected to originate from a former swamp area.

Basuki and his team found evidence that the gas source is located in a river area approximately 300 metres from the house. At the site, there are dark-coloured rock outcrops with stagnant water emitting gas bubbles.

‘We found gas bubbles that are likely methane, CH4. It’s directly beneath the Nepen Road bridge,’ he said at the site on Saturday (30 May 2026).

‘So, the first indication – as this is still an initial investigation – is that the gas source is methane from a former swamp. This strongly suggests the area’s bedrock was once a swamp,’ he explained.

One-Month Monitoring Plan

Basuki assessed the site as relatively safe, but his team will monitor the area to ensure stability.

‘The gas seems to have decreased, with no signs of fire. We expect to wait about a month; if there are no further gas emissions, we may classify the incident as moderate or minor,’ he said.

Basuki added that, based on initial checks, the gas does not have high pressure and is not particularly dangerous.

‘In essence, God willing, the gas is not hazardous as its pressure is low,’ he explained.

Methane Accumulates in Household Items

Dr. Sarju Winardi, a lecturer and assistant professor in UGM’s Geological Engineering Department, revealed that methane gas had accumulated in various items in Mutfiana’s house.

The findings were obtained through thermal camera temperature measurements, which showed fire hotspots in areas with relatively higher temperatures.

According to Sarju, methane shares similarities with household LPG, but requires a specific concentration before igniting.

‘Methane is like having an LPG stove at home, but it has a lower release rate and calorific value. It needs a higher concentration to ignite,’ he said.

Therefore, Sarju explained that methane seeping from the ground is likely accumulating in porous household items such as clothing, fabrics, and sofas.

‘It sometimes takes a while. It accumulates on sofas, clothing, and fabrics, and only ignites once sufficient quantities build up,’ he said.

He explained that porous materials can store certain amounts of gas. If enough accumulates, it can potentially cause fires.

‘Items with pores, like clothing and sofas, will hold the gas. When enough accumulates and meets oxygen, it ignites,’ he said.

Testing Gas Content in Water

Sarju also stated that further measurements will be conducted to determine gas content, particularly in water from pipes and wells that previously produced flames.

‘We may bring equipment next week to measure gas levels at the site and water samples. Since gas previously emerged alongside water pipes and wells that produced flames, we will test if the water is contaminated with methane,’ he explained.

Sarju explained that, theoretically, methane-contaminated water does not ignite while underground. Flames occur when the water surfaces and the methane is released into the air.

‘Ignition happens when the water surfaces and interacts with oxygen, releasing methane. It’s the methane escaping from the water that causes combustion,’ he said.

Recommend Improved Air Circulation

Based on these findings, Sarju recommended improving air circulation in the house. Residents were advised to install fans or blowers to accelerate air exchange and prevent methane buildup.

‘We recommend enhancing ventilation by installing fans or blowers to prevent methane accumulation on materials like clothing or sofas,’ he said.

However, Sarju noted the risk of methane spreading to neighbouring houses is low. Methane tends to rise and disperse into the atmosphere, rapidly reducing its concentration.

‘Once outside, it mixes with ambient air, causing levels to drop significantly, making it relatively safe. Opening ventilation reduces concentration and fire risk,’ he concluded.

Previously reported, repeated fires occurred at Mutfiana’s house in Seyegan, Sleman, over the past week. The Gegana police unit inspected the site, and UGM deployed experts to investigate the mysterious flames.

The fires began on Saturday (23 May) and occurred 39 times by Thursday (28 May), burning items such as fabrics, furniture, and other flammable materials.

‘There have been 39 fires across 34 different points. Furniture, clothing, mats, and other flammable items were burned. But it’s strange – the top parts burned while the bottom didn’t,’ Mutfiana said when interviewed at her home on Thursday (28 May 2026).

Mutfiana reported the incident to the police, who deployed the Gegana unit. Their findings concluded a septic tank leak caused the flammable methane gas.