Abstract: This study aims to reveal the relationship between the geological and geomorphological structure ofthe Adapazarı city center, which was largely destroyed by the earthquakes on 17 August 1999 (Mw: 7.4) and 12 November 1999 (Mw: 7.2), and the existing settlement areas and location selection of development areas. Adapazarıcity center, which is located on the Adapazarı Plain, has an alluvial soil structure carried by the Sakarya Riverand where the underground water level is quite high. Adapazarı was the most affected city by the 17 August and 12 November 1999 earthquakes, due to liquefaction. The Central Planning Region, which includes the entire Adapazarı city center, has been accepted as the study area within the scope of the Sakarya province 1/100,000 scale Land UsePlan for 2025, which was approved on 07.01.2010. The relationship between the geological-geomorphological structure of the study area and the city has been revealed by overlaying aerial photographs, satellite images, digital elevation models, and digital data obtained by using Geographical Information Systems (GIS). The objective of thestudy is to investigate the effect of the geological and geomorphological structure on the urban pattern after the  1999 earthquakes. The geological and geomorphological factors affecting the urban development were weightedby the Analytical Hierarchy Process (AHP) method and their relationship with the changing urban pattern was discussed. After obtaining the synthesis map by overlapping the thematic maps, it was found that the constructionson unsuitable land (65% of the study area) continued after the 1999 earthquakes. The newly developed areas locatedin the northmost part of the existing city center are suitable for settlement in terms of geology and geomorphological criteria.