The dense micro-earthquake activity at the boundary between the Anatolian and South Aegean microplates

The Aegean coast of Turkey is a transition zone between the Anatolian and the South Aegean microplates. The recent geophysical studies suggest the existence of additional microplates and suggest a modification of the block boundaries; the Karaburun Peninsula is most likely located on one of these boundaries. The earthquake activity in and around the peninsula was very low until the Mw 5.8 Sığacık Bay earthquake of 17 October 2005. The continuing seismicity in the Karaburun Peninsula has been monitored with the help of the dense seismology network. I re-located more than 5000 earthquakes using the double-difference algorithm and obtained fault plane solutions to understand the seismotectonic properties of the region. It is found that the micro-seismic activity has increased towards the NW of the Sığacık Bay. These observations imply the existence of a NW–SE-oriented sinistral strike-slip fault. This fault is possibly a conjugate of the dominant NE–SW-oriented dextral strike-slip faults in this transition region occupying the area between western Anatolia and the mainland of Greece, where a dominantly extensional regime prevails. Moreover, it is clear that the micro-earthquake activity is related to the Uzunkuyu Intrusive located in the middle of an approximately 40 km strike-slip Karaburun Seismic Zone between the Sığacık and Gerence bays.

► A new seismic deformation zone is observed in Western Turkey.
► Karaburun Deformation Zone is a segment of the Anatolian and South Aegean boundary.
► Micro-earthquakes indicate that the Uzunkuyu Intrusive dips to NW.