Microzonation for earthquake hazards: Yenişehir settlement, Bursa, Turkey

Abstract

Detailed geological, hydrogeological and geotechnical studies were performed for the assessment of the foundation conditions of the present and future settlement areas of Yenişehir. Yenişehir is located 50 km east of Bursa, Turkey, within an east–west trending elliptical sedimentary basin. The present and future development areas of Yenişehir cover 10 km2. The topography of the settled area is quite smooth and the slopes are generally less than 10°. Yenişehir is located within a First-Degree Earthquake Zone of Turkey according to the seismic design code. The seismicity of the town is mainly controlled by the Geyve-İznik and Bursa fault zones. The study also involves trial pitting, drilling, in situ testing and laboratory testing. Borehole logs, index properties of soils, standard penetration test results and groundwater level measurements were used for activity and liquefaction assessments of the foundation material. Based on the evaluation of the data, two geotechnical zones were distinguished. The northern part of the area is characterized by cohesive soils of high expansion behaviour and the southern part by alternation of cohesive and non-cohesive soils showing high liquefaction potential.