{
  "id": "son-doong-survey-2009",
  "title": "Sơn Đoòng: separating an immense cave from an inflated story",
  "country": "Vietnam",
  "category": "nature",
  "date": "2009-04-01",
  "date_label": "April 2009 survey month; the first day is an ordering anchor, not a precise discovery time",
  "location": "Phong Nha–Kẻ Bàng, Quảng Bình",
  "lat": 17.458,
  "lng": 106.287,
  "summary": "Explorers surveyed a gigantic cave passage in 2009. The case distinguishes local discovery, expedition documentation and what a world-record size claim actually measures.",
  "sources": [
    {
      "id": "SD1",
      "title": "UNESCO — World Heritage decision 39 COM 8B.6",
      "url": "https://whc.unesco.org/en/decisions/6356",
      "language": "en",
      "note": "Official description qualifies the size claim and exploration date.",
      "kind": "Source record · see provenance note"
    },
    {
      "id": "SD2",
      "title": "Oxalis — discovery and exploration",
      "url": "https://oxalisadventure.com/son-doong-cave-discovery-and-exploration/",
      "language": "en",
      "note": "Local exploration and operator account; commercial interest is explicit.",
      "kind": "Source record · see provenance note"
    }
  ],
  "author": "Eklipsis",
  "content_languages": [
    "en"
  ],
  "path": "/investigations/son-doong-survey-2009",
  "source_url": "https://whc.unesco.org/en/decisions/6356",
  "location_source_url": "https://www.openstreetmap.org/?mlat=17.458&mlon=106.287#map=8/17.458/106.287",
  "location_precision": "region",
  "location_note": "Approximate orientation marker for the named place or institution; not a surveyed observation point, protected excavation coordinate or recommended access route.",
  "reviewed_on": "2026-09-30",
  "edition": 1,
  "truth_type": "unknown",
  "verdict": "The cave and its exceptional dimensions are documented. The interesting question is how surveys support a particular comparison, not whether an immense space implies an unknown civilisation. No invented subterranean creature or unexplored tunnel is added.",
  "sections": [
    {
      "title": "Documented account",
      "text": "The exploration account credits Hồ Khanh with leading the 2009 team to the entrance. UNESCO’s 2015 decision describes Sơn Đoòng as first explored in 2009 and believed to contain the largest cave passage in terms of diameter and continuity. Cave passage size, total length and total volume are different measurements; the word largest must retain its metric.",
      "refs": [
        "SD1",
        "SD2"
      ]
    },
    {
      "title": "Evidence and its limits",
      "text": "The point is regional orientation, not an underground route. A tourism operator’s exploration account has direct local knowledge and a commercial interest. A cave survey should retain its measurement method and date rather than replacing them with a superlative.",
      "refs": []
    },
    {
      "title": "Inspector’s assessment",
      "text": "The cave and its exceptional dimensions are documented. The interesting question is how surveys support a particular comparison, not whether an immense space implies an unknown civilisation. No invented subterranean creature or unexplored tunnel is added.",
      "refs": []
    },
    {
      "title": "A reproducible next investigation",
      "text": "Make a provenance table for the local entrance discovery, surveyed sections and subsequent announcements. Compare passage cross-section, length and volume using compatible definitions. Keep later additions to a survey separate from the first expedition’s documented extent.",
      "refs": []
    }
  ],
  "timeline": [
    {
      "date": "Local discovery history",
      "text": "Hồ Khanh identifies the entrance before the survey expedition.",
      "refs": [
        "SD1"
      ]
    },
    {
      "date": "April 2009",
      "text": "The expedition reaches and surveys the cave.",
      "refs": [
        "SD1"
      ]
    },
    {
      "date": "2015",
      "text": "UNESCO’s decision describes the cave in the enlarged heritage property.",
      "refs": [
        "SD1"
      ]
    },
    {
      "date": "30 September 2026",
      "text": "Eklipsis prepares this source-linked documentary synthesis. This is editorial review, not historical fieldwork.",
      "refs": []
    }
  ],
  "claims": [
    {
      "text": "Explorers surveyed a gigantic cave passage in 2009. The case distinguishes local discovery, expedition documentation and what a world-record size claim actually measures.",
      "status": "Documented subject; interpretations qualified in the dossier",
      "refs": [
        "SD1"
      ]
    },
    {
      "text": "The cave and its exceptional dimensions are documented. The interesting question is how surveys support a particular comparison, not whether an immense space implies an unknown civilisation. No invented subterranean creature or unexplored tunnel is added.",
      "status": "Assessment with explicit limits",
      "refs": [
        "SD1"
      ]
    },
    {
      "text": "The map point represents the exact location of every reported event.",
      "status": "Incorrect; orientation only",
      "refs": []
    }
  ],
  "hypotheses": [
    {
      "title": "Exceptional karst passage formation",
      "status": "Geological framework",
      "support": "A measured cave passage is consistent with karst development.",
      "limits": "A complete formation history needs geological research.",
      "test": "Compare bedrock, hydrology and dated geological observations."
    },
    {
      "title": "Differences in the meaning of largest",
      "status": "Measurement qualification",
      "support": "Length, diameter and volume are different quantities.",
      "limits": "A ranking cannot be established by one photograph.",
      "test": "Use the same quantity and survey standard for compared caves."
    }
  ],
  "tasks": [
    {
      "title": "Audit the source record",
      "body": "Retrieve the named records for Sơn Đoòng: separating an immense cave from an inflated story. Record author, edition, page or section and access date. Treat a catalogue, mirror or translation of one document as the same evidence, not independent corroboration."
    },
    {
      "title": "Build the dated evidence ledger",
      "body": "Make a provenance table for the local entrance discovery, surveyed sections and subsequent announcements. Compare passage cross-section, length and volume using compatible definitions. Keep later additions to a survey separate from the first expedition’s documented extent."
    },
    {
      "title": "Test the interpretation",
      "body": "Compare bedrock, hydrology and dated geological observations. Use the same quantity and survey standard for compared caves. Record what would favour or weaken each explanation; leave unperformed work marked as proposed."
    }
  ]
}