September 5, 2026 | 07:31 pm
TEMPO.CO, Jakarta - The rumbling and vibrations heard by some residents in West Java, Banten, and Lampung on Friday night to Saturday morning, September 4-5, 2026, were not mysterious. The rumbling and vibrations that were discussed on social media were caused by the eruption of Mount Anak Krakatau in the Sunda Strait.
"We suspect that it is indeed related to the eruption activity of Mount Anak Krakatau that occurred at the same time (as the rumbling and vibrations)," said the Head of the Centre for Volcanology and Geological Hazard Mitigation (PVMBG), Siti Sumilah Rita Susilawati, in a virtual press conference on Saturday, September 5, 2026.
According to Rita, a similar phenomenon had occurred during the eruptions of several volcanoes in Indonesia. She cited reports from residents in Jakarta, Bogor, Depok, Tangerang, and Bekasi who heard rumbling sounds on April 11, 2020, which were also related to the eruption of Mount Anak Krakatau.
"We tried to match the timing in 2020, and it indeed corresponded to the eruption of Mount Anak Krakatau on April 10, 2020, at 21:58 and 22:35 WIB (Western Indonesia Time)," she said.
Rita added that this suspicion was strengthened by the Meteorology, Climatology, and Geophysical Agency (BMKG)'s report, which stated that there were no significant tectonic earthquakes in West Java, Banten, or Lampung during that time period.
Rita explained that the simultaneous timing was an indication of correlation. However, it did not definitively prove identification of the rumbling's source. She continued, "But the propagation of eruption sounds over a long distance is a phenomenon that may occur."
Rita also cited the explosive eruption of Mount Kelud in East Java on February 13, 2014. The rumbling sound was heard as far as Yogyakarta and Central Java, which are relatively far from the volcano on the border of Kediri, Blitar, and Malang.
"During the eruption of Mount Kelud, with a column of 17 kilometers, it released a very large amount of acoustic energy. So, based on the data we have, including the literature we obtained, there is a possibility that eruptions can be heard at a considerable distance," she said.
When a volcano erupts, Rita explained, the focus is not only on the eruption's strength but also its type. Rita said that Mount Anak Krakatau's lava fountain eruption is usually accompanied by loud rumbling sounds.
"When that happens, the release of its acoustic energy can be very large, and this acoustic energy can spread over hundreds of kilometers," she added. "There have been studies investigating this, and it can be heard in some distant areas."
Rita stated that the eruption of Mount Anak Krakatau, which was the source of the rumbling and roaring sounds heard in the Banten, West Java, and Lampung regions, specifically originated from the eruption that occurred on Friday night, September 4, 2026, at 22:17 WIB.
The eruption was reported to be ongoing until Saturday morning, when the press conference was held. "We are still monitoring the ongoing eruption at Anak Krakatau Volcano," she said.
Rita said that the current eruption of Mount Anak Krakatau had not posed any imminent danger that required a change in the volcano's activity status. The status of Anak Krakatau remained at Alert Level III, and the danger zone remained within a 3-kilometer radius of the volcanic activity center.
"So, please pay attention to the 3-kilometer radius, which is indeed dangerous and could be caused by the eruption of incandescent lava," she said.
Read: Will Mount Anak Krakatau Eruption Trigger Tsunamis? BNPB Assures It Won't
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Today's Top 3 News: Mount Anak Krakatau Erupts, 6 Volcanoes Erupt on Aug. 31
1 jam lalu
Here is the list of the top 3 news on Tempo English today.
Will Mount Anak Krakatau Eruption Trigger Tsunamis? BNPB Assures It Won't
7 jam lalu
BNPB has urged coastal communities to remain calm amid concerns about the tsunami risks triggered by the ongoing eruption of Mount Anak Krakatau.
Mount Anak Krakatau Erupts Overnight, Spews Lava Fountains
9 jam lalu
Mount Anak Krakatau erupted overnight into Saturday, September 5, 2026. A total of six eruptions were recorded.
Are Indonesia's 6 Volcano Eruptions on Aug. 31 Linked? PVMBG Explains
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PVMBG reported that six volcanoes, including Mount Sinabung, erupted across Indonesia on August 31. Are those events interconnected?
Mount Anak Krakatau Erupts 13 Times on Wednesday
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PVMBG recorded 13 eruptions from Mount Anak Krakatau in South Lampung Regency, Lampung Province.
Mount Anak Krakatau Erupts Six Times in a Single Morning
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Anak Krakatau erupted six times from morning to midday Monday, sending volcanic ash columns up to 250 meters above its summit in the Sunda Strait.
Mount Anak Krakatau Spews Incandescent Lava in Recent Eruption
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The volcanic activity of Mount Anak Krakatau has picked up since June.
Mount Anak Krakatau Erupts 8 Times, Ejects Lava Up to 300 Meters
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Mount Anak Krakatau erupted eight times, ejecting incandescent lava up to 300 meters, while authorities maintained its Level III alert status.
Indonesia Debunks Hoax Video of Mount Anak Krakatau Eruption
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Indonesia's Geological Agency reminds the public not to be lured by misleading information regarding Mount Anak Krakatau Volcano.
Mount Anak Krakatau Status Escalated to Level III Alert
3 Juli 2026
The Geological Agency has raised the activity status of Mount Anak Krakatau to Level III (Siaga), enforcing a 3-km exclusion zone from the crater.
