Une catastrophe naturelle majeure : l'écroulement du Mont Granier dans le massif de la Chartreuse au XIII^e siècle

A major geological hazard: The rockslide avalanche of the Granier montain during tbe XIII^th century

Abstract

On the north end of the Chartreuse range, the rockfall of the Granier mountain which occured in november 1248 is explained by a huge landslide. The mechanism of this translational slide is probably the water vaporisation produced by the rock speed along a bedding joint in the Valanginian marlstones. This landslide induced the fall of the calcareous urgonian cliff, the debris can be recognized as extending for over 7,5 km. This geological hazard was not a single event, older landslides occured on the Granier slopes and even now an instability is still proved. These intermitting movements are connected with living faults.