%0 Journal Article
%T Large gravitational rock slope deformation in Romsdalen Valley (Western Norway) Deformaci車n gravitacional de las vertientes rocosas del valle de Romsdalen (Noruega occidental)
%A Aline Saintot
%A Thierry Oppinkofer
%A Marc-Henri Derron
%A Lain Henderson
%J Revista de la Asociaci車n Geol車gica Argentina
%D 2012
%I Asociaci車n Geol車gica Argentina
%X Large gravitational rock slope deformation affects Precambrian gneisses at four localities of the Romsdalen valley of Western Norway. At each locality, detailed studies have allowed to determine the mechanism of deformation and to assess the degree of susceptibility for failure. 1) Svarttinden is a 4.3 Mm3 translational rockslide. Its single basal detachment developed along a foliation-parallel cataclastic fault. Although a rockslide occurred along the same detachment and the deposits reached the edge of the plateau, no displacement of the current instability is detected. 2) At Flatmark distinct 2-25 Mm3 blocks detached from the edge of the plateau by an opening along the steep foliation. The collapse of the blocks is explained by a complex mechanism of sliding and toppling. No displacement is actually detected on the instabilities. 3) At B ra blocks located at the edge of the plateau deformed by the same mechanism as at Flatmark. They have a maximum volume of 0.5 Mm3 and displacement rates of 0.2-2 cm/year. The deformation at B ra has affected a large part of the plateau and the entire deformed volume would be of 50-200 Mm3 but it is currently inactive. 4) A wedge failure at the edge of Mannen plateau is inferred to allow the 4-5 cm/year downward displacement of a 2-3.5 Mm3 instability. The high susceptibility of failure led to a permanent monitoring of the site since 2009. Una gran deformaci車n gravitacional afecta unidades gn谷isicas prec芍mbricas en cuatro localidades del valle Romsdalen, Oeste de Noruega. En cada localidad, estudios detallados permitieron determinar el mecanismo de deformaci車n y evaluar el grado de susceptibilidad al colapso. 1) Svarttinden es un deslizamiento translacional de 4.3 Mm3. Su plano basal se desarroll車 a lo largo de una falla paralela a planos con deformaci車n catacl芍stica. Si bien un deslizamiento tuvo lugar a lo largo del mismo plano basal, y los dep車sitos alcanzaron el borde del plateau, no se detecta desplazamiento en la zona inestable. 2) En Flatmark, bloques de 2-25Mm3 se desprendieron del borde de la meseta a partir de la apertura de planos de foliaci車n de gran inclinaci車n. El colapso de bloques es explicado por un complejo mecanismo de deslizamiento y volcamiento. No se detecta actualmente desplazamiento en las zonas inestables. 3) En B ra, bloques ubicados en el borde de la meseta fueron deformados por el mismo mecanismo que en Flatmark. Los mismos tienen un volumen m芍ximo de 0.5 Mm3 y tasas de desplazamiento de 0.2-2 cm/a. La deformaci車n en B ra ha afectado gran parte de la meseta y el total del volumen deformado
%K Deslizamiento
%K An芍lisis estructural
%K Mecanismo
%K Rockslide
%K Structural analysis
%K Mechanism
%U http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0004-48222012000300004