Το UkrSA ανακοίνωσε νέο βάθος -2158μ και έσπευσε να "δικαιολογήσει" τις παλαιότερες χαρτογραφήσεις του... Προχώρησαν επίσης σε μετρήσεις με υδροστατική πίεση όπως έκανε το CAVEX πριν έναν χρόνο και (μετά την εισήγηση των Provalov - Zharkov στο 14th ICS πέρυσι στην Αθήνα) ανακοίνωσαν το αναμενόμενο σφάλμα των μετρήσεων τους...
Το μήκος του σπηλαίου έχει ανέβει στα 10 km...
NEWS FROM THE ⌠CALL OF THE ABYSS■ PROJECT
(see also http://www.speleogenesis.info/spotlights/krubera.php)
In the period between August 19 - September 20, 2006 the Ukrainian
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,
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
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 reached 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).
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 -
-- Alexander Klimchouk, the CA Project coordinator,
based on the report by Yury Kasjan, the expedition leader