Mysterious underground phenomenon rocks village in East Java, Indonesia

INDONESIA: Residents of Moncek Tengah Village in Lenteng Sub-district, Sumenep, East Java, were left bewildered by a series of loud booming sounds and ground vibrations that emanated from beneath the earth’s surface.

The enigmatic sounds, reminiscent of digging and accompanied by tremors, first began on Saturday (12 Aug) between 9:00 AM and 11:00 AM local time. The source of the phenomenon is suspected to be beneath five houses in the village’s central area.

Local concerns led villagers to seek help from the village administration, the Regional Disaster Management Agency (BPBD), and the local police.

Lenteng Sub-district Police Chief, Assistant Police Commissioner Bondan Wibowo, stated that, according to local reports, the strange noises and vibrations persisted for about 30 to 45 minutes, from around 9:45 AM to 10:30 AM.

Out of the five houses in the suspected epicenter area in Dusun Tengah, RT 07, RW 02, Moncek Tengah Village, three houses were identified as potential sources of the mysterious sounds and vibrations.

As a precautionary measure, residents of these three houses were advised to evacuate temporarily to prevent any untoward incidents.

Hazmi (30), a resident of Dusun Tengah, described the escalating phenomenon. He explained, “The underground sounds began about 10 days ago but were sporadic. Today, the noise grew louder, and the vibrations were felt by several homeowners.”

Sumenep Residents Pointing Out Location of Mysterious Underground Sounds. (Photo: Special/captured from amateur resident video)

In response to the mysterious occurrence, the Meteorology, Climatology, and Geophysics Agency (BMKG) intervened, dispatching a geophysics team from the Pasuruan branch to investigate the phenomenon on Sunday, August 13, 2023.

The investigation included the installation of a seismograph in the affected area to collect essential data related to the origin of the booming sounds.

On Monday (14 Aug), Suwarto, Coordinator of Observation and Information at BMKG Pasuruan, explained the limitations of the seismograph in determining the cause of the phenomenon.

“The seismograph records vibrations, but it cannot provide direct conclusions. Additional data and methods are needed, such as geoelectric, geomagnetic, or gravity measurements. Integration of various methods is necessary for comprehensive analysis.”

Since the installation of the seismograph on Sunday (13 Aug), there have been no further serious reports of continued underground sounds and vibrations like those experienced on the morning of Saturday (12 Aug).

Further investigations will be conducted by the Center for Volcanology and Geological Hazard Mitigation (PVMBG), which plans to send experts to the site with specialized equipment.

“Thorough on-site examination is necessary using Ground Penetrating Radar (GPR) or geoelectric methods, as this is an issue concerning shallow subsurface matters,” stated Hendra Gunawan, Head of PVMBG Badan Geologi.

As the community awaits the results of these comprehensive investigations, the source of the mysterious booming sounds and ground vibrations remains a puzzling enigma that experts are diligently working to unravel.