F. Purtscheller et al., RADON EMANATION FROM GIANT LANDSLIDES OF KOEFELS (TYROL, AUSTRIA) ANDLANGTANG-HIMAL (NEPAL), Environmental geology, 26(1), 1995, pp. 32-38
Citations number
35
Categorie Soggetti
Water Resources","Environmental Sciences","Geosciences, Interdisciplinary
The identification of extremely high indoor radon concentrations in th
e village Umhausen (Tyrol, Austria) initiated a scientific program to
get information about the source and distribution of this noble gas. T
he high concentrations can not be related to U anomalies or large-scal
e fault zones. The nearby giant landslide of Koefels, with its highly
fractured and crushed orthogneisses, are the only possible source of r
adon, despite the fact that the U and Ra content of the rocks is by no
means exceptional. The reasons for the high emanation rates from the
landslide are discussed and compared to results gained from a similar
examination of the giant landslide of Langtang Himal (Nepal). The exce
ptional geologic situation in both cases, as well as the spatial distr
ibution of different concentration levels, indicate that both landslid
es must be considered as the production sites of radon. Independent of
the U and Ra contents of the rocks, the most important factors produc
ing high emanation rates are the production of a high active surface a
rea and circulation pathways for Rn-enriched soil air by brittle defor
mation due to the impact of the landslidemass.