NEOTECTONICS AND SEISMICITY OF THE DENIZLI GRABEN, SOUTHWESTERN TURKEY

Located in southwestern Turkey, the Denizli Graben is about 50 km in length and about 25 km in width. It is bounded by the Pamukkale fault zone to the NE and the Babadag and Honaz fault zones to the SW. The Babadag fault zone is generally made up of one fault in the vicinity of the town of Babadag where it dips about 35-45 degrees NE and separates the metamorphic rocks in the footwall from the sedimentary rocks in the hanging wall. However, the fault becomes segmented to the south of the town of Denizli and contains many overlapping branches and exhibits an excellent example how the strain partitions towards the end of a large normal fault before it dies out. The Honaz fault is located along the SW margin of the Denizli Graben and strikes approximately E-W. The Pamukkale fault also contains many overlapping segments in the Denizli area along the NE margin of the graben. The overlapping branches of the fault zone are likely locations for travertine deposits. The Denizli Graben contains a NW-SW trending horst controlled by oppositely dipping high angle normal faults which truncate the Plio-Quaternary rock units. The faults that bound the Denizli Graben were probably initiated during the Late-Miocene to Early and are still active. Earthquake record indicate that 15 earthquakes with magnitudes ranging from 5 to 6 had occurred in the Denizli area from 1900 -2004. There is no earthquake bigger than Magnitude 6 in this time interval. However, the earthquake that destroyed the ancient Roman town of the Hierapolis in B.C. 60 may be bigger than magnitude 6. The Denizli region is also known by frequent but small earthquakes. There were 158 earthquakes with magnitude between 2.9 to 5.0 in the last 9 months of the year 2000.