--- title: "Krakatau Erupted On Sunday. Nine Sensors On Gunung Padang Heard A Room 22 Metres Down." dek: "The volcano that closed Jakarta's airport gave a hill in West Java its loudest seismic source in a century. Nine buried instruments used it. Between 22 and 26 metres there is a void with a flat floor and a flat roof." kind: news (News) desk: Deep History author: Dr. Perpetua Nkemelu and Dr. Ilse Vantongeren (fictional) published: 2026-09-06T10:15:00Z url: https://theyburied.com/article/nine-sensors-heard-a-room tags: Gunung Padang, Anak Krakatau, West Java, passive seismic, Indonesia genre: satire status: fiction — nothing in this story happened; every person, source and document is invented --- # Krakatau Erupted On Sunday. Nine Sensors On Gunung Padang Heard A Room 22 Metres Down. *The volcano that closed Jakarta's airport gave a hill in West Java its loudest seismic source in a century. Nine buried instruments used it. Between 22 and 26 metres there is a void with a flat floor and a flat roof.* At 05:38 on Sunday morning, Western Indonesian Time, the ground under Gunung Padang began to shake, and it went on shaking for seventy-one minutes. The source was Anak Krakatau, two hundred kilometres to the west, whose eruption closed Jakarta's airport by lunchtime. On the terraces of a hill above Cianjur it did something else. It lit up nine seismometers that had been buried there since June, listening for three months to nothing louder than a road. By 11:00 the array's principal investigator had an image. Between 22 and 26 metres below the top terrace there is a volume where the waves slow almost to nothing. It is fifteen metres long, four metres high, and its top and bottom are flat. The floor is flat. That is the finding. > **Figure:** Gunung Padang, under Terrace 1, as of Sunday afternoon — see https://theyburied.com/article/nine-sensors-heard-a-room ## The peg The Associated Press reported the eruption as an aviation story: flights cancelled at Jakarta and elsewhere. That is what it was for most of Java. For nine instruments on a hill in Cianjur it was the loudest thing to pass through the ground in a century. ## The hill Gunung Padang is a terraced hill of columnar basalt, four levels stepping up a ridge, excavated to the terrace floors between 2012 and 2014. What is above the floors nobody disputes: stacked columns, some mortared, arranged by people. In 2023 a paper in a geophysical journal said the hill went on being built for a long way down, in three units, the deepest dated to more than twenty thousand years ago. In March 2024 the journal retracted it. The dates, the retraction said, were on soil, and nothing tied the soil to anything a person had made. The retraction was about years. It said nothing about whether there was structure at depth. The deep units stayed disputed and the excavation permit stayed suspended, as it has been since 2014. ## What was on the hill already Dr. Wisnu Adiputra-Halvorsen of Bandung and Dr. Femke Ruysdael-Okafor of Utrecht buried nine broadband seismometers on the terraces in June, under a permit that allows instruments and forbids blades. The method uses whatever shakes the ground, traffic and surf and weather, and over months builds a picture of how fast waves travel through the rock. Slow means loose, or wet, or hollow. Three months of the road to Cianjur produced, in Dr. Adiputra-Halvorsen's word, a smear: a slow zone somewhere between fifteen and twenty-five metres, with no shape. Then the volcano gave them seventy-one minutes of a source a thousand times louder. > For three months we listened to a road. Then the ground rang like a bell for an hour and we could see. > > — Dr. Wisnu Adiputra-Halvorsen ## What the tremor shows The time the tremor took to cross from one station to the next is the whole of the data. Under Terrace 1, between 22 and 26 metres, the waves slow to a speed that is not sand and is not wet basalt. Dr. Adiputra-Halvorsen's velocity model puts it at air. The volume is fifteen metres long on the axis of the terraces, about four metres high, and its upper and lower surfaces are sharp on the image to within half a metre. A lava tube has a rounded roof. A collapse cavity has an irregular one. This has a flat one, and a flat floor under it. Dr. Ruysdael-Okafor has the same data in an airport in Singapore and is running it through a different code. She will not say what it shows because she has not let herself look. Her reply, at the foot of this page, says why. ## The man who swapped the cards The stations write to memory cards and send a low-rate copy over a cellular modem. The full-rate data, which is what the image needs, was on the cards. At first light on Sunday Pak Dadang Sumarna-Oyelaran, who has looked after the site since 2009, walked the terraces and swapped all nine, without being asked, because the investigators had told him in June that if the ground ever shook he should not wait. He had them in a plastic bag at the site office by 07:15. The image exists because of that walk. ## The permit The array's permit is for nine buried instruments. Excavation below the terrace floors has been suspended since 2014, and the directorate confirmed on Sunday afternoon that no application to resume it is on file. The investigators will not make one. It is not their field. What they can give the ministry, as of Sunday, is a set of coordinates and a depth, to within a metre. ## What this desk takes from it For three years the argument about this hill has been about a number of years, and the number is no closer today than it was on Saturday. What is closer is the hole. There is a volume of air fifteen metres long under Terrace 1, with a flat floor, and a volcano told nine instruments where it is. Somebody with a permit and a drill could put a camera into it in a week, as this newspaper did under another hill last month. The second image is being run by a woman who has promised not to look until it is finished. When it is, we will print it, whether it shows the room or shows that we should not have called it one. ## Sources (invented) - Dr. Wisnu Adiputra-Halvorsen, Seismologist, Bandung; principal investigator of the Cianjur array — Interviewed by telephone at 06:40, 09:10 and 14:00 on Sunday; sent us the tremor tomography and his processing log as he produced them (6 September 2026) - Dr. Femke Ruysdael-Okafor, Seismologist, Utrecht; co-investigator of the array — Reached by telephone in Singapore, where her connecting flight to Jakarta was cancelled; has the raw data and is processing it independently (6 September 2026) - Pak Dadang Sumarna-Oyelaran, Site caretaker, Gunung Padang, since 2009 — Interviewed in person on the terraces on Sunday afternoon; walked our correspondent to all nine instruments (6 September 2026) - The Cianjur array's deployment permit and station log, June to September 2026, Nine broadband seismometers, buried at 60 centimetres on Terraces 1 to 4 — Permit photographed with the investigators' consent; station log published in full with this story (June–September 2026) - Directorate of Cultural Heritage, Ministry of Culture, Jakarta, Excavation permits, Gunung Padang, 2011 to present — Written questions on Sunday morning; a two-sentence answer by mid-afternoon (6 September 2026) ## What we could not confirm - The second image. Dr. Ruysdael-Okafor has the same data and has not finished with it. Until she has, this story rests on one processor working through one night, and she has told us she will not be hurried by a newspaper. - What is in the void. A velocity image says a volume is slow, and slow enough here to be air rather than sand. It does not say what is on the floor, and it does not say how old the floor is. The dating argument that got the 2023 paper retracted is not settled by this. It is not touched by it. - Whether anybody will be allowed to look. Excavation below the terraces has been suspended since 2014. The investigators' permit covers nine buried instruments and nothing with a blade. No application to dig has been made, and the directorate told us on Sunday that none is on file. ## Right of reply **Dr. Femke Ruysdael-Okafor, co-investigator, the Cianjur array** (Replied at 17:10 by email. Asked that her reply run whole rather than as a quote. Printed unedited.): > I am in an airport and I have read your draft on a telephone, so forgive the length of this. I would rather be long than be quoted. > > Wisnu's image is a good image. I have known him for nine years and I have never seen him get an arrival time wrong. If he says there is a slow volume between 22 and 26 metres with a sharp top and a sharp bottom, there is a slow volume there, and I would not have said so this morning, and I am saying it now. > > Here is what I want your readers to hold on to. A seismometer measures how long a wave takes to cross a piece of ground. That is all. Wisnu and I put nine of them on that hill in June to listen to traffic and weather and the sea, and the sea is quiet and the traffic is a road, and for three months we got a smear. Then a volcano went off two hundred kilometres away and for seventy-one minutes the ground shook hard enough to give us the picture we had wanted. That is luck, and it is the good kind, and it is still luck. > > What it is not is a date. Your headline says a room. The paper that was retracted in 2024 said a pyramid twenty-seven thousand years old, and it was retracted because the dates were on soil and not on anything a person made. Nothing in Wisnu's image has changed that argument by a single year. A void with a flat floor is a void with a flat floor. Lava does that sometimes. People do it more often. I do not know which this is and neither do you and, for the avoidance of doubt, neither does he. > > I have the raw data on the laptop in front of me and I am running it now, on a different code, with a different velocity model, and I have not looked at the output and I will not look at it until it is finished, because I know what I want to see and that is precisely the moment a scientist should stop trusting her eyes. When it is done you will have it, whether it agrees with him or not. That is a promise and the second half of it is the important half. > > One more thing, since you have been so careful to print the permit. We are not going to apply to dig. It is not our hill and it is not our field. If the directorate wants to know what is at 22 metres, it knows where the hole should go, to within a metre, as of this morning. That is what we can give them. What they do with it is a decision for people who are not in an airport. --- They Buried is a satirical newspaper. Every story, source, document and person in it is invented. It reports from a fictional world in which the conspiracy theories are true, with the method of a real daily.