The effects of the North Anatolian Fault on the geomorphology in the Eastern Marmara Region, Northwestern Turkey

Abstract

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.

Morphotectonic analysis of the East Anatolian Fault, Turkey

“…The resolution of the DEM limited the degree of uncertainty associated with the geomorphic indices. We do not assign an uncertainty to our geomorphic indices as in other studies (e.g., El Hamdouni et al, 2008;Tari and Tüysüz, 2015). …”

Yeşilırmak Havzası Yukarı Mecrasında Almus Fayı Boyunca Drenajın Gelişimi

“…Undoubtedly, some geomorphological properties are associated with these climatic changes. However, according to Tarı and Tüysüz (2015) the geomorphological differences or anomalies seen in the study area likely derive from lithological differences and tectonics, rather than climate. If there is no important climatic disparities in a region and the lithology remains consistent, in this case, anomalies in stream profiles can be attributed to tectonic processes affecting the area (Tarı and Tüysüz, 2015).…”

“…However, according to Tarı and Tüysüz (2015) the geomorphological differences or anomalies seen in the study area likely derive from lithological differences and tectonics, rather than climate. If there is no important climatic disparities in a region and the lithology remains consistent, in this case, anomalies in stream profiles can be attributed to tectonic processes affecting the area (Tarı and Tüysüz, 2015). Therefore, tectonic processes were more affective on drainage development than climatic changes since traces of glaciation from the Pleistocene do not exist in mountainous areas around the study area.…”

“…The most important parameters affecting the deposition and entrenchment of alluvial fans are tectonics and climate (Pepin et al, 2010;Salcher et al, 2010). There is a close relationship between climate and sea level changes in the Black Sea region (Tarı and Tüysüz, 2015). Palaeoclimate records indicate that prominent climatic changes have been formed in the Black Sea region since 600 ka (Badertscher et al, 2011).…”

Seismic risk assessment using updated hazard and building inventory data

“…[15,16]. Regional seismic risk assessment studies can also be found in the literature about various methods that are used for scenario-based earthquakes with deterministic and probabilistic earthquake hazard [23][24][25][26][27][28]. Earthquake damage and loss estimations were also conducted for the IMM, where the seismic hazard and expected risk are known to be high [17][18][19].…”