Effects of Geological and Petrographic Factors on Landslide Development in the North of Biga Peninsula, NW Turkey

Abstract

The study includes landslide movements that occurred on Eocene and Middle-Upper Miocene terrestrial and marine sedimentary units in the Biga Peninsula. In this study, three active landslide areas in Ambaroba, Şevketiye and Adatepevillages located on the northern coastof the Biga Peninsula were investigated. Geological studies ofthe Ambaroba landslide show the integrity of the Bayramiç formation and the Şapcıvolcanics in this area were influentialin the Miocene period. The sandstones in the Bayramiç formation are not very well consolidated, and are yellow, dirty yellow and gray in color. The sliding surface units in the moving masses consist of unconsolidated, very large blocky, pebbly and loosely cemented pebbles. In the Şevketiye and Adatepe landslides, sliding movement occurred on sandstone and conglomerate units with yellowish brown colors in the Fıçıtepe formation. The sandstones in these landslide areas are massive and well cemented. Conglomerates are weaker than sandstones with a gray-beige colorand no consolidation. Precipitation data and Global Positioning System measurements of the landslide areas were evaluated together with the lithological properties of the rocks. Loose sandstones and pebbles in the entire landslide areas can easily move due to seasonal precipitation. This movement was mostly seen in the Şevketiye landslide area and then in the Adatepe and Ambaroba areas, respectively. Although their effectiveness has decreased, movements will continue as the lithological features will not change in these areas. As a result, the measures specified in this study should be considered in order to eliminate the destructive effects of landslides.