Mysterious Boom Over Bandung-Sumedang, BMKG Suggests 'Skyquake' as Potential Cause

A loud, unexplained boom was reported by multiple residents in the Bandung and Sumedang areas of West Java, Indonesia, from Friday night (September 4, 2026) to early Saturday morning (September 5, 2026). The Meteorology, Climatology, and Geophysics Agency (BMKG) has pointed to 'skyquake' as a potential temporary cause for the phenomenon. Suaidi Ahadi, head of the BMKG Bandung Geophysics Station, stated that the boom is highly likely to be a skyquake. A skyquake is a natural phenomenon described as a loud noise from the sky, even on clear days, with its exact cause remaining unidentified. Ahadi noted that a similar event occurred in Bogor in 2020, but its cause also went unexplained. Wijayanto, Director of Earthquakes and Tsunamis at BMKG, reported that investigations into seismic and lightning activity during the time of the boom did not reveal any significant events that could explain the sound. BMKG's seismic monitoring data showed no earthquake activity in or around Bandung between 00:00 and 05:00 WIB on September 5. Lightning detector data also indicated low-intensity lightning activity, not significant enough to account for the reported boom. The boom gained traction on social media. Threads user @aldianty1717 (Sri Lung Dianty) posted about hearing the sound from the direction of the sky in Sumedang around 01:00 WIB. She mentioned that even by 06:36, her house doors were still vibrating with the sound every 20-30 minutes, causing distress among residents. Another user, @lilgramofm, initially mistook the sound for someone walking on their roof. While the exact cause of this mysterious boom remains undetermined, BMKG plans to continue its investigation.