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| Titel |
Rock failure propagation since last glacial age (10kyears) in the south-eastern French Alps : the La Clapiere Deep Seated Landslide |
| VerfasserIn |
S. El Bedoui, T. Lebourg, Y. Guglielmi, J.-L. Pérez |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250031246
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| Zusammenfassung |
| The “La Clapière” area (Tinée valley, Alpes Maritimes, France) is a typical large, complex,
unstable rock slope affected by Deep Seated Gravitational Slope Deformations (DGSD)
with tension cracks, scarps, and a 60Ã106 m3 rock slide at the slope foot that is
currently active. The slope surface displacements since 10 ka were estimated from 10Be
ages of slope gravitational features and from morpho-structural analyses. It appears
that tensile cracks with a strike perpendicular to the main orientation of the slope
were first triggered by the gravitational reactivation of pre-existing tectonic faults
in the slope. A progressive shearing of the cracks then occurred until the failure
of a large rock mass at the foot of the slope. By comparing apertures, variations
and changes in direction between cracks of different ages, three phases of slope
surface displacement were identified: 1) an initial slow slope deformation, spreading
from the foot to the top, characterized by an average displacement rate of 4 mm
yr-1, from 10–5.6 ka BP; 2) an increase in the average displacement rate from 13
to 30 mm yr-1 from the foot to the middle of the slope, until 3.6 ka BP; and 3)
development of a large failure at the foot of the slope with fast displacement rates
exceeding 80 mm yr-1 for the last 50 years. The main finding of this study is that
such a large fractured slope destabilization had a very slow displacement rate for
thousands of years but was followed by a recent acceleration. The results obtained
agree with several previous studies, indicating that in-situ monitoring of creep of a
fractured rock slope may be useful for predicting the time and place of a rapid failure. |
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