# Were Train, Slow Down and Julia made by icebergs grounding on the seafloor? · Bloop and NOAA's unexplained ocean sounds > Three answers have been proposed. All three were produced by large icebergs settling on or dragging across the seafloor. leads, with evidence 2 for, 1… Source: https://mysteriesdept.com/mysteries/noaa-ocean-sounds/questions/QST0D9C7D1J3NMQ/were-train-slow-down-and-julia-made-by-icebergs-grounding-on Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) Updated: 2026-10-26T11:58:17+00:00 --- **0** # Were Train, Slow Down and Julia made by icebergs grounding on the seafloor? Asked 26 Oct 2026 by [**apollo** ](https://mysteriesdept.com/u/apollo)·Part of [What made the loud unidentified sounds recorded by NOAA's Pacific hydrophones in the 1990s?](https://mysteriesdept.com/mysteries/noaa-ocean-sounds/questions/QST0D9C7CA41BJB/what-made-the-loud-unidentified-sounds-recorded-by-noaas)·3 answers·0·0 following **Most likely: all three were produced by large icebergs settling on or dragging across the seafloor** Ahead on the evidence, not yet confirmed. It needs two reviews to be accepted. ## Where it stands Three answers have been proposed. All three were produced by large icebergs settling on or dragging across the seafloor. leads, with evidence 2 for, 1 against: partly supported by its tests. Two are still possible. ## Why it matters NOAA assigns all three to iceberg groundings from their tonal or descending shape and bearings toward the Ross Sea and the Antarctic Peninsula⁠[[1]](https://mysteriesdept.com/sources/SRC0D9C71JC5TEP/acoustics-monitoring-program-iceberg-grounding-train)⁠[[2]](https://mysteriesdept.com/sources/SRC0D9C71AJ57W0/acoustics-monitoring-program-iceberg-grounding-on-seafloor)⁠[[3]](https://mysteriesdept.com/sources/SRC0D9C72202TZM/cryogenic-ice-sounds). Grounding signals have since been studied with the iceberg in view, which gives a direct comparison⁠[[4]](https://mysteriesdept.com/sources/SRC0D9C73GW1MV0/life-and-death-sounds-of-iceberg-a53a)⁠[[5]](https://mysteriesdept.com/sources/SRC0D9C74G44MTQ/hydroacoustic-signals-generated-by-parked-and-drifting). ## Answers 3 [**All three were produced by large icebergs settling on or dragging across the seafloor.** ](https://mysteriesdept.com/mysteries/noaa-ocean-sounds/answers/ANS0D9C7PAE07W8/all-three-were-produced-by-large-icebergs-settling-on-or) Partly supported by its tests Evidence: 2 for, 1 against Most likely [**None of these.** ](https://mysteriesdept.com/mysteries/noaa-ocean-sounds/answers/ANS0D9C7QHG19KA/none-of-these) Not tested enough to call either way Evidence: none yet Still possible [**Some of the three are groundings and others are different sources (for example icequakes or tremor from bergs…** ](https://mysteriesdept.com/mysteries/noaa-ocean-sounds/answers/ANS0D9C7Q9P772G/some-of-the-three-are-groundings-and-others-are-different) Not tested enough to call either way Evidence: none yet Still possible ## History 1. 2006[Talandier et al.: grounded and drifting bergs produce long-range hydroacoustic signals catalogued in the southern Indian and…](https://mysteriesdept.com/sources/SRC0D9C74G44MTQ/hydroacoustic-signals-generated-by-parked-and-drifting)For: All three were produced by large icebergs settling on or dragging across the seafloor. 1. 2013[Dziak et al.: iceberg A53a produced harmonic tremor while scraping shoals, recorded on nearby hydrophones.](https://mysteriesdept.com/sources/SRC0D9C73GW1MV0/life-and-death-sounds-of-iceberg-a53a)For: All three were produced by large icebergs settling on or dragging across the seafloor. 1. 26 Oct 2026Asked on this site ## Discussion 0 [Add to the discussion](https://mysteriesdept.com/signin?next=/mysteries/noaa-ocean-sounds/questions/QST0D9C7D1J3NMQ/were-train-slow-down-and-julia-made-by-icebergs-grounding-on%23discussion) Help with this question [ **Propose an answer** Something the evidence could support or rule out ] [ **Propose an answer** Something the evidence could support or rule out ](https://mysteriesdept.com/signin?next=/mysteries/noaa-ocean-sounds/questions/QST0D9C7D1J3NMQ/were-train-slow-down-and-julia-made-by-icebergs-grounding-on%23add-answer) [ **Add evidence** A result for or against an answer ] [ **Add evidence** A result for or against an answer ](https://mysteriesdept.com/signin?next=/mysteries/noaa-ocean-sounds/questions/QST0D9C7D1J3NMQ/were-train-slow-down-and-julia-made-by-icebergs-grounding-on%23add-evidence) [ **Ask a sub-question** A smaller question that would help settle this one ] [ **Ask a sub-question** A smaller question that would help settle this one ](https://mysteriesdept.com/signin?next=/mysteries/noaa-ocean-sounds/questions/QST0D9C7D1J3NMQ/were-train-slow-down-and-julia-made-by-icebergs-grounding-on%23add-question) [ **Add a source** A paper, archive record or image ] [ **Add a source** A paper, archive record or image ](https://mysteriesdept.com/signin?next=/mysteries/noaa-ocean-sounds/questions/QST0D9C7D1J3NMQ/were-train-slow-down-and-julia-made-by-icebergs-grounding-on%23add-source) Where it fits Bloop and NOAA's unexplained ocean sounds [**What made the loud unidentified sounds recorded by NOAA's Pacific hydrophones in the 1990s?** ](https://mysteriesdept.com/mysteries/noaa-ocean-sounds/questions/QST0D9C7CA41BJB/what-made-the-loud-unidentified-sounds-recorded-by-noaas)Key question · most likely all of them are natural geophysical or cryogenic sounds (icequakes, grounding icebergs, volcanic eruptions… [Was the Bloop an icequake, and from which iceberg?](https://mysteriesdept.com/mysteries/noaa-ocean-sounds/questions/QST0D9C7CHY4R4M/was-the-bloop-an-icequake-and-from-which-iceberg)Most likely · the Bloop was one or more icequakes from a large iceberg cracking somewhere between Bransfield Strait and the… **Were Train, Slow Down and Julia made by icebergs grounding on the seafloor?** You're here · all three were produced by large icebergs settling on or dragging across the seafloor [Where did Whistle come from?](https://mysteriesdept.com/mysteries/noaa-ocean-sounds/questions/QST0D9C7D9C6V99/where-did-whistle-come-from)Most likely · whistle was an eruption signal from a distant submarine arc volcano [ Ask a question under this one ]