Le glissement de terrain d'avril 1996 à Saint-Boniface-de-Shawinigan, Québec : observations et données préliminaires

Abstract

During the afternoon of April 21, 1996, a massive landslide occurred in Champlain Sea sediments along the Machiche River, 5 km south of St-Boniface-de-Shawinigan, Quebec. The slide occurred in a wooded area following a period of intense rainfall. The landslide is thought to be a multiple retrogressive type with a volume estimated to be about 8 X 106 m3. It is one of the largest landslides (31 ha) to have occurred in the St-Lawrence Lowlands in this century. The debris blocked the valley of the Machiche River and caused a lake to form upstream. This landslide has shown the vulnerability of hydroelectric facilities and roads to major landslides in Champlain Sea sediments.