The Determination of the Slip Rates of Main Fault Zones Driving Turkey's Neotectonics and the Formationof Block Deformation Models Through Geodetic Methods

Project Manager:  Prof. Dr. Haluk Özener
 
Abstract:
Turkish Active Fault Map published in 1992 by General Directorate of Mineral Research and Exploration provided a template for various research studies. However, a comprehensive revision study was initiated in view of the developments in earth sciences in the last 20 years and it was completed in 2012. The revised active fault map involves twice as many active faults as the previous active fault map. The revised fault map shows that there are about 500 active faults in Turkey. The seismotectonic map of Turkey is needed to use the active fault map which was revised through aerial photography, satellite imagery and geological field studies in earthquake hazard prediction and assessment. In this respect, it is necessary to analyze the active faults through seismological and geodetic data and to determine the fault zones which accumulated high strain energy. Therefore, it is required to determine the fault slip rates of main active faults in Turkey through geodetic methods. The most common method for this purpose is to use GPS observations. In parallel to his concept, the directorate of Disaster and Disaster Management initiated National Earthquake Strategy and Action Plan-2023 which involves Action A.1.1.4 (Monitoring and modeling of interseismic, coseismic and postseismic crustal deformation with national geodetic networks), Action A.2.1.2 (Determination of fault slip rates to obtain some of the parameters of active faults) and Action A.2.1.1 (The preparation of 1/250000 scale active fault maps and seismotectonic maps and visualization of some of fault parameters through GIS capabilities). Similarly, the preparation of the seismotectonic map of Turkey is also included in the strategy and action plan. While various local studies exist, the slip rates of many active faults in Turkey are not available. The slip rates are the most common input to produce the seismotectonic maps.The block modeling is also a very common method to determine the fault slip rate through geodetic observations. GPS velocity filed required for block modeling will be compiled from the literature, will be computed from the raw observations obtained from the organizations and will be combined. Various stochastic models will be analyzed to produce a homogeneous and optimal velocity field. GPS velocity fields are combined globally to produce Global Strain Map which involves strain analysis of sparse data sets.In this study, a similar attempt is made for Turkey but with a more comprehensive and detailed analysis. For instance, this study involves the computation of fault slip rates as opposed to strain analysis in Global Strain Map Project. Moreover, an advanced variance component analysis is also planned to optimally combine the GPS velocity fields. In this project; the data from Turkish National Permanent GPS Stations, the data from Turkish National Permanent GPS Stations–Active and Turkish National Fundamental GPS Network will be obtained, episodic GPS measurements will be done at selected points, the GPS data available in the literature will be compiled, new stochastic models will be developed and a homogenous combined velocity field will be produced. This combined velocity will be used to infer the fault slip rates through block modeling. The output of the project will the fault slip rate map of main active faults of Turkey and will be one of the most important inputs of Turkish Seismotectonic Map.