The Saint-Jean-Vianney Landslide: Observations and Eyewitnesses Accounts

Abstract

A major landslide occurred in Champlain Clay at Saint-Jean-Vianney, Quebec, on May 4, 1971. Preliminary investigations reveal that the slide commenced about 10.15 p.m., hit the east section of the town about 10.55 p.m., and within 5 min carried 40 homes to destruction and 31 persons to their deaths. An estimated 9 × 106 cubic yards (6.9 × 108 m3) of material moved during the slide, from an area of approximately 350 000 square yards (~268 000 m2). The slide commenced within the crater of a much larger landslide that occurred about 500 years ago, and after complete liquefaction travelled down the Rivière aux Vases at a speed of approximately 16 miles/h (~26 km/h), carrying debris out into the middle of the Saguenay River.A detailed geotechnical study of the landslide region is currently under way.