Sifoni a meno 2000 metri, roba da far accapponare la pelle, 5 sifoni laggiù in fondo, uomini che ci vanno e due organizzazioni russe a farsi la “guerra” delle esplorazioni con due diversi sistemi di misura e rilevamento, e ovviamente su due chilometri le differenze iniziano ad essere rilevanti.. Tutto il mondo guarda alla Krubera intanto, quella che ha infranto il muro dei -2000.

Apprendiamo la notizia da Gianni Garbelli e Matteo Rivadossi:

Dal 19 agosto al 20 settembre 2006 si è svolta una nuova spedizione russa-ucraina alla volta di Krubera (massiccio di Arabika, Abkazia): protagonisti stavolta non gli amici del Cavex Team ma 16 speleologi guidati da Yurj Kasjan sotto la supervisione del vecchio Alexander Klimchouk.
I principali risultati esplorativi hanno riguardato il fondo del Ramo Non-Kujbyshevskaja (quello del grave incidente del 2005, per intenderci) dove, oltre la frana di -490, una squadra si è fermata a
-1004 m senza più materiale e la zona più profonda della grotta dove il fortissimo Gennady Samokhin ha pensato bene di immergersi nel quinto sifone.
Ben 40 metri con 14 di profondità che spostano verso l’inferno il punto più basso mai raggiunto dall’uomo: -2158!

Il resto della notizia in Italiano si trova sul sito del Gruppo Grotte Brescia: http://www.ggb.it 

In inglese, dalla Grecia, le notizie arrivano da Zenas con il World Caving News:

Speleological Association (Ukr.S.A.) and the Ukrainian Institute of
Speleology and Karstology (UISK) have conducted a regular expedition of the
CA Project to Krubera (Voronja) Cave in Arabika Massif, Abkhazia.

The expedition was led by Yury Kasjan and consisted of 16
speleologists from Ukraine (from Kiev, Kharkov, Simferopol,
Sevestopol, Poltava, Dnepropetrovsk and Kamenetz-Podilsky) and Russia
(Moscow and Irkutsk). New explorations have been made in different parts of
the cave, including the lowermost part, as well as various scientific
observations.

A major progress has been achieved in the Nekujbyshevskaja Branch (a
distinct branch diverging from the main one at -250m and stretching to the
north-west, the direction opposite to the overall trend of the main branch)
by a team led by Kirylo Markovskoj.

They continued exploring a new part, discovered and pushed to a boulder
choke at -643m a year ago after breaking through the upper boulder choke at
-490m. During this expedition the choke at -643m has been also broken and
the branch pushed to -1004m, a point where the team run out of rope.

The work in the lower part of the main branch can be summarized as follows:

1) The lowermost part below the Kvitochka siphon at -1980m has been
resurveyed. The depth of the post-siphon section (to the spit at the table
of the Two Captains siphon, the one at the bottom) is measured to be 164m.

2) The Two Captains siphon has been dove by Gennady Samokhin for 40m in
length and 14m in depth, to the point where he was stopped by a squeeze. So,
the new overall depth of Krubera Cave is now -2158m (see notes on survey
data below). The absolute elevation of the lowermost eached point in the
cave is about 100m a.s.l. but it still far (more than 12km) from the Black
Sea coast where the discharge from the system occurs.

3) Some new explorations have been made in the lower part of the cave: an
ascending side passage at -1710m has been explored for 150m/+20m; a dry
bypass of the siphon Unitaz at -2068m has been found; a siphon at -1775m
(first tested in August 2004) has been dove by G.Samokhin, who passed a
narrow place at -10m but stopped at an underwater boulder choke in the
ascending leg.

The scientific program in this expedition included geological observations,
various sampling (clastic sediments for mineralogic analysis, microbiologic
materials, speleothems for U-series dating), temperature measurements (over
200 measurements through the depth profile in both the main branch and
Nekujbyshevskaja) and observations of the groundwater level fluctuations
from past flood evidences.

The latter suggest that the water level may arise during a year up to
approximately -1700m, the fluctuation for more than 450m (during spring
snowmelt floods or major rainfalls).

The updated map of the whole Krubera Cave will be published soon.

Krubera total depth: -2,158m
Krubera total length: 10,870m

Notes on the survey data and depth measurements:

The complete integrated Krubera survey dataset, maintained by the Ukr.S.A.
through many years, consists of more than 1850 vectors to the date. Survey
is performed using Suunto compasses KB-14, clinometers PM-5 (or Tandem
instruments) and Leica-Disto meters or fibron tapes (older surveys in the
upper parts have been re-done during last several years).

During the October 2005 Ukr.S.A. expedition to Krubera Cave a team from the
Moscow Branch of the Russian Geographic Society (T.Nemchenko and
A.Degtjarev), supported by the Bulgarian cavers, has conducted an
independent thorough hydro-levelling work from the entrance to 1194m in the
main branch, in order to verify the actual precision of depth figures
obtained from the standard survey.

A comprehensive methodological substantiation for the technique, and the
analysis of errors involved, has been performed by A.Degtjarev, E.Snetkov
and A.Gurjanov of Moscow (available in Russian in Svet n.29, 2005 and at
<http://www.rgo-speleo.ru/biblio/hydroniv.htm>
http://www.rgo-speleo.ru/biblio/hydroniv.htm ).

They demonstrated that the correct application of the hydro-levelling
technique allows measuring depth with the 0.2% accuracy, i.e. with an error
of 4m for a 2000m depth. At the same time, they estimated that the combined
error in determining depth due to some commonly practiced improper
procedures could be up to 2%.

The roundtripping closure (up and down measurements) for the section 0-916m
(80 measurements), performed in October 2005, gave an error of 0.05m. i.e.
less than 0.01%. Therefore, the results of this survey can be reasonably
taken as an etalon dataset.

Comparison of the standard Ukr.S.A. survey with the etalon data for
particular points in the 0-1194m interval has revealed actual errors varying
between +0.97 and -1.37 %, with an average error being 0.9%. Based on this,
the overall accuracy of the Ukr.S.A. standard survey in depth measurements
is assumed to be 1.0%.

The results of another hydro-leveling work, performed by the
Moscow-based Cavex team in July-August 2005 and claimed to correct the
Ukr.S.A. figure for the old bottom from -2080m to -2064m (to -2047m in other
sources), have been shown to suffer from improper procedures involved.

Comparison of their results with the etalon data for particular points shows
the actual error of the Cavex hydro-levelling measurements varying within
-0.64 and -2.2% (average 1.2%), which is even greater than the errors of the
standard Ukr.S.A. survey as compared to the same etalon. Therefore, there is
no reason for correction for the figure previously reported by the Ukr.S.A.
for the old bottom .

CONCLUSION: The overall error of the standard Ukr.S.A. survey is proven to
be within 1%. The current depth of Krubera Cave, reported here as -2158m,
has the margins of possible error between +22m and -> 22m.

— Alexander Klimchouk, the CA Project coordinator, based on the report by
Yury Kasjan, the expedition leader.

 

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