Deciphering the Dynamics of the Simav Fault in Western Turkey

Lindsey German

Simav Mountain Range
Photo taken looking south at the Simav Mountain range. The red line represents the Simav Fault.

On May 19, 2011, a Mw 5.8 earthquake occurred 9.1 km below the surface of the Earth on the Simav Fault in western Turkey. Conflicting interpretations for the mechanism or mechanisms that caused faulting exist: several studies indicate dextral strike-slip motion on the fault while alternative work associates the deformation with large-scale, N-S post-collisional extension.  In addition, the geographical extent of the structure is also unclear. Observations from Digital Elevation Models (DEMs) and geophysical data provide information on the structural relationships in the Simav region.  Multiple maps are used in this study to determine if the topography in the region can be used to gain information regarding the Simav Fault. Visual representations for focal plane solutions and high topographic relief suggest that the Simav Fault has been influenced by normal faulting, most likely a result of the post-collisional extension that has prevailed in western Turkey since the Late Miocene. A Digital Elevation Model generated in ArcGIS displays the fault trending WNW-ESE, extending at least from the towns of Sindirgi to Sincanli with a total extent of about 180 km. Earthquake epicenters and hypocenter distances cluster within this range. Parallel lineaments in the study area indicate that the Simav Fault may be part of a broader zone of deformation. Dextral offset of streams and volcanoes coupled with the focal plane solution for the Simav Earthquake (May 19, 2011; Mw 5.8) suggest the existence of a dextral strike-slip component in the region. This project will provide valuable information to those interested in the tectonic and structural implications of the area and help to better constrain seismic hazard risk assessments that directly influence the structural community.

Advisor: Elizabeth Catlos