Abstract: During the 17 August 1999 Marmara earthquake in Türkiye, the surface rupture became indistinct north of Aydınpınar village in the southeast of Düzce Basin at the eastern end of the rupture. The surface rupture of the 17 August 1999 earthquake propagated towards the west, but it also propagated towards the east reaching the southeast of Düzce Basin. Thus fault propagation after 17 August developed towards the east to cause the later Düzce-Kaynaşlı earthquake on 12 November 1999 where the surface rupture propagated reaching Asarsuyu valley in Kaynaşlı county. Although an İstanbul earthquake is expected in the near future, we aim to draw attention to the segment in the furthest east of this zone. In this area, increasing earthquake risk is indicated by the development of a series of tensional gashes in the north of the Bolu Basin and an M=4.8 earthquake that occurred in this region on 16 March 2023.