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The Kinematic Properties of The Southwest Extension of Fethiye-Burdur Fault Zone
One of the marked tectonic structure in Southwest Anatolia is Isparta angle. Fethiye-Burdur fault (FBF) zone forms the western branch of the Isparta angle. Two major events of M7 class took place on this zone: the 03.10.1914 Burdur and the 25.04.1957 Fethiye earthquakes. These events obviously showed that an important accumulation of deformation exist along this fault zone and heretofore earthquakes may cause loss of life and property in this area.
In this thesis, we compile an earthquake focal mechanism data set for M≥4.0 events that took place starting from 1914 to present and covering the region between 34o-38,5o N latitude and 25o-31o E longitude. The data was compiled from various catalogs and the analysis of 26 focal mechanisms was done within the scope of this study. This analysis showed that the region is an active tectonic complex. As a result we compiled a data set of 252 fault plane solutions to inverstigate the structural relationship between the southwest extension of Fethiye-Burdur fault zone and the Hellenic Arc. The disagreement between the rake of the fault plane salutions of events taking part in NE part of FBF zone and the GPS vektor is striking. Although, the earthquakes show that NW-SE extension in the region is a predominant feature the GPS data indicate right-lateral strike slip motion in NE-SW direction. Disagreement exists between the earthqukes in southwetsern part of FBF zone and the GPS data, as well. The upper crust earthquakes in Cameli basin show NNE-SSW extension while the GPS data suggests NW-SE compression.
Using the fault plane solutions in our data set we estimated the stress tensor acting in SW Anatolia that yield results showing direction and plunge of the principle stress axes as 1=(123, 65), 2=(278, 23), 3=(12, 10). Similarly, for the region to the southwest of FBF zone we obtain principal stress axis parameters as 1=(205,1), 2=(115, 8), 3=(304, 82).
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