## 3 Geological Structure and Fault Blocks Onshore and Offshore Samos
### Fault Blocks  
The Samos Island comprises the following fault blocks (Figure 5):  
1. The western fault block of Samos is bounded to the north and south by fault zones that bound Kerketeas Mt to the north and south, respectively, while to the east it is bounded by the marginal fault zone of the Karlovasi basin. It has been rotated around an E-W trending horizontal axis resulting in the uplift of its northern part in three tectonic episodes characterized by variations in frequency and magnitude and the subsidence of the southern part in one episode [27]. During the last tectonic episode, the northern part presented an uplift of 0.70 cm and its southern part a subsidence of 0.60 cm [27]. The uplift of the northwestern part of Samos Island has been verified by the interdisciplinary study on Holocene shorelines conducted by [28]. They found that three raised shorelines approximately 0.6, 1.1, and 2.3 m above sea level (a.s.l), which were assigned to historical and paleo- earthquakes generated 500, 3600 \(\pm\) 3900, and possibly 1500 years ago.
2. The Mytilini basin constitutes an N-S-striking graben initially formed in the Lower-Upper Miocene, filled with sediments in the Miocene-Pliocene and faulted in the Pleistocene [7]. It has been developed between the marbles and schists of the mountainous Ampelos area and the zone of marbles and schists of Vathy-Agia Zoni [4; 7].
3. The Karlovasi basin was formed in the western part of Samos between the Ampelos and Marathokampos units with a general N-S strike and has been filled with Neogene formations.  
* The Pyrgos basin constitutes a NW-SE-striking narrow elongated graben separating the mountainous area of Ampelos from Bournias. Taking into account the deposition and evolution processes, the Pyrgos basin seems to be a part of the Mytilinii basin. Neogene beds strike from NW-SE to N-S and dip 20-50\({}^{\circ}\) generally to NE and E.
* The fault block of eastern Samos has suffered a total subsidence of 0.50 m taking into account [27]. The western boundary of this fault block coincides with the Vathy-Psili Ammos fault zone. The aforementioned subsidence of the southeastern part of Samos has been also verified by [29]. They showed that the southeastern part of Samos underwent subsidence at least during the late Holocene, with relative sea level rise rates of 0.8 mm/yr.
* The fault block of central-southern Samos is a second fault block that acted independently, undergoing successive phases of initial uplift and a subsequent subsidence of 0.20 m around an E-W-trending axis [27]. The northern boundary of this fault block coincides with the E-W-trending fault zone passing through the Limnonaki area, while the eastern and western boundaries coincide with the eastern and western fault zones of the Karlovasi and Mytilinii basin, respectively. As regards the northern part of Samos, local uplift has been detected based on uplifted beach rocks [27].
* A 15-km-wide asymmetric graben-like structure prevails in the area offshore northern Samos [3; 6; 10]. It is bounded by a major E-W-striking and northward-dipping fault zone comprising faults in an en echelon arrangement, which played a significant role during the formation of the structure and shaped the coastal morphology of northern Samos [3; 6; 10].