North-western Anatolia has been actively deformed since Pliocene by the right-lateral North Anatolian Fault (NAF). This transform fault, which has a transtensional character in its western end due to effects from the Aegean extensional system, is a major control on the regional geomorphologic evolution. This study applied some geomorphic analyses, such as stream longitudinal profiles, stream length-gradient index, ratio of valley floor width and valley height, mountain front sinuosity, hypsometry and asymmetry factor analyses, to an area just east of the Sea of Marmara in order to understand the tectonic effects on the area’s geomorphological evolution. The active and fastest northern branch of the NAF lies within a topographic depression connecting Sea of Marmara in the east to the Adapazarı Basin in the west. This depression filled with early Pleistocene and younger sediment after a series of pull-apart basins opened along the NAF. North of this depression lies the Kocaeli Peneplain, whose southern edge the NAF uplifted. Meandering streams on the central peneplain were incised possibly due to baselevel changes in the Black Sea. South of the depression, an E-trending mountainous area has a rugged morphology. Based on geomorphic analyses, uplifted Pliocene sediment, marine terraces, and recent earthquake activity, this area between northern and southern branches of the NAF is actively uplifting. The geomorphic indices used in this study are sensitive to vertical movements rather than lateral ones. The bedrock lithology that played an important role on the area’s geomorphologic evolution also affects the geomorphic indices used here.

中文翻译：

---

北安纳托利亚断层对土耳其西北部东马尔马拉地区地貌的影响

自上新世以来，安纳托利亚西北部一直受到右侧北安纳托利亚断层（NAF）的积极变形。该转换断层受爱琴海伸展系统的影响，其西端具有横张特征，是区域地貌演化的主要控制因素。本研究对马尔马拉海以东的一个地区应用了一些地貌分析，如河流纵剖面、河流长度梯度指数、谷底宽度与谷高比、山前曲折度、测高和不对称因子分析。了解构造对该地区地貌演化的影响。NAF 活跃且速度最快的北部分支位于连接东部马尔马拉海和西部 Adapazarı 盆地的地形洼地内。在一系列拉开盆地沿 NAF 打开后，这个洼地充满了早更新世和较年轻的沉积物。该洼地以北是科贾埃利半平原，其南部边缘 NAF 隆起。中央准平原上蜿蜒的溪流被切割，可能是由于黑海的基线变化。在洼地以南，一个 E 趋势的山区具有崎岖的地貌。根据地貌分析、上新世抬升的沉积物、海相阶地和最近的地震活动，NAF 南北分支之间的这一区域正在积极抬升。本研究中使用的地貌指数对垂直运动而不是横向运动敏感。对该地区地貌演化起到重要作用的基岩岩性也影响了这里使用的地貌指数。