Geologiczne warunki rozwoju osuwiska w Brzeżance koło Strzyżowa

Abstract

GEOLOGICAL SETTING OF DEVELOPMENT OF LANDSLIDE AT BRZEŻANKA NEAR STRZYŻÓW Summary The landslide from northern sloes of Bonarówka Hill at Brzeżanka near Strzyżów became active in December 1974. First movements were recorded in October 1974 and the maximum translocations – in December 24, 1974, when 6 buildings were destroyed. The mass movements from these slopes are dated at about 130 years and larger-scale translocations were recorded in a 1967 am 1969. The landslide from Brzeżanka developed at northern margin of the Bonarówka patch, in the zone of overthrust of the Silesian Unit on the Subsilesian (Figs. 3, 4). The SiIesian Unit is here represented by Upper Wierzowskie shales (Barremian - Aptian) and Lgockie Beds (Aptian - Albian) and the Subsilesian Unit - by mottled shades and marls of the Senonian - Eocene. The origin of the landslide was directly related to intense precipitation from the last quarter of 1974 (Fig. 5).