Sector:USA/Veryovkina_Cave_Depth

## Metadata

**Incident ID:** INC-2024-3791

**Date:** Multiple entries 2016–2024 (report compiled 2024-09-12)

**Location:** Veryovkina Cave, Arabika Massif, Gagra Mountain Range, Abkhazia (coordinate grid withheld in source documents)

**Reporting Agency:** PSC (Pskov Speleological Club) — primary reporting entity; PST (Petersburg Speleological Team) referenced in historical entries

**Status:** UNRESOLVED

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## Abstract

A series of speleological surveys and diving operations were conducted in Veryovkina Cave between 2016 and 2024. Incremental increases in maximum recorded depth were documented in successive expeditions. Instruments and procedures were described in expedition logs. Two discrete data elements from the compiled record remain without technical explanation after intra-agency review: (1) an anomalous acoustic recording during the 2017 deep descent and (2) a persistent depth measurement discrepancy between an underwater drone survey in August 2023 and a subsequent expedition survey in August 2024. All other survey records, field notes, photographic files, and instrument calibration records have been reviewed and are presented in this case record.

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## Chronological case record

All chronological entries were recorded in the PSC archive format and were transcribed verbatim from expedition logs. Passive voice is used in the following summaries to reflect archival tone.

- 2012–2015: The pre-2016 baseline depth was held at 440 m (1,440 ft) in regional speleological archives. The baseline was cited in PSC internal briefings as the deepest verified depth prior to 2016 entries.

- August 2016: A joint PST/PSC expedition was conducted. The ascent/descent timetable was logged as 2016-08-12 through 2016-08-25. A maximum vertical extent of 1,010 m (3,310 ft) below the surface was recorded. Measurements were produced by a combination of photographic tape measures (metric), laser rangefinder readings where open passage allowed, and redundant altimetry derived from calibrated barometric instruments. Surface conditions on 2016-08-12 at 07:00 local time were recorded as overcast skies, air temperature 12°C, wind 5 m/s from the north. The entrance shaft was described as shaded; no direct sunlight was noted in the entrance chamber at 07:12. Sounds of running water were described on approach and throughout the upper series; no mechanical noise was present. The primary descent team was listed as three persons: two male members of PST (heights recorded as 1.82 m and 1.75 m; clothing recorded as insulated overalls, helmets with mounted LED headlamps of 200 lumen rating, single-digit glove sizes) and one PSC member (height 1.68 m; clothing recorded as soft-shell jacket and harness). Rope systems were described as dynamic single-rope techniques; anchor points were described in the log with coordinates relative to the entrance lip.



- October 2016: A PST-only expedition was conducted. A maximum vertical extent of 1,350 m (4,430 ft) was recorded. Sur