The Northern Branch of the North Anatolian Fault System controls and deforms the Izmit Basin and the Sapanca Lake Basin in the study area. Unlike the Sapanca Lake Basin, the oblique normal faults with WNW–ESE trending with maximum length of 5 km in the south of the basin have contributed to the deformation process in the formation of Izmit Basin. The fault sets mainly incline to the north. The N-S width of the dextral strike-slip active deformation was determined as 9 km at Izmit basin and 3.8 km at Sapanca Lake basin. Further, the minimum principal stress axes (σ3) vary in the trending ranges of N11°–74°E, which are caused by the transtensional stresses associated with strike-slip faulting in the Izmit Basin by a different tectonic source than the Sapanca Lake Basin. Besides, the crust depth of main strand of NAFS-NB was determined up to 1112 m by magnetic method. The secondary faults were determined by both magnetic and resistivity methods up to a depth of 110 m. The depression area between Izmit bay and Sapanca Lake on the northern Anatolian fault is an integrated basin with two dextral strike-slip tectonic origins. Thus, the Izmit Basin, along with the main strike-slip faulting, has been developed in the asymmetric negative flower structure, where only the southern boundary has become a fault. The Sapanca Lake Basin is a lazy-Z-shaped pull-apart system formed by the E–W trending fault as a releasing bend. A simple shear deformation ellipsoid with a long axis of approximately 35 km on the Northern Branch of the North Anatolian Fault System is defined for the Izmit–Sapanca integrated basin. Therefore, intra-basin deposits have different depths estimated from the gravity data in the Izmit–Sapanca integrated basin, and the maximum sediment thickness estimated is 2200 m in the middle of the Izmit Basin.

北安纳托利亚断层系统的北支控制和变形研究区的伊兹米特盆地和萨潘卡湖盆地。与 Sapanca 湖盆地不同，盆地南部最大长度为 5 km 的 WNW-ESE 向斜正断层促成了 Izmit 盆地形成的变形过程。断层主要向北倾斜。右旋走滑活动变形的 NS 宽度在 Izmit 盆地确定为 9 km，在 Sapanca Lake 盆地确定为 3.8 km。此外，最小主应力轴（σ3) 在 N11°–74°E 的趋势范围内变化，这是由与 Sapanca 湖盆地不同构造源的 Izmit 盆地走滑断层相关的张应力引起的。此外，NAFS-NB主链地壳深度为1112 m，由磁法确定。次生断层由磁法和电阻率法确定，深度可达 110 m。位于安纳托利亚断层北部的伊兹米特湾和萨潘卡湖之间的坳陷区是一个具有两个右旋走滑构造起源的综合盆地。因此，伊兹密特盆地连同主走滑断裂发育在不对称负花结构中，只有南边界成为断层。萨潘察湖盆地是一个由东西向断层作为释放弯形成的懒惰Z形拉分系统。伊兹密特-萨潘卡综合盆地在北安纳托利亚断层系统的北分支上定义了一个长轴约 35 公里的简单剪切变形椭球。因此，根据伊兹米特-萨潘卡综合盆地的重力资料估计盆地内沉积物的深度不同，估计伊兹米特盆地中部的最大沉积厚度为2200 m。