Accuracy Assessment of Mesh Types in Tectonic Modeling to Reveal Seismic Potential Using the Finite Element Method: A Case Study at the Main Marmara Fault

Abstract

Earthquakes occur as a result of ruptures on faults along plate boundaries. It is possible to reveal the approximate location and magnitude of the earthquake rupture, but this requires that the seismic cycle and kinematics of the study area are well known. Different measurement methods and modeling techniques are used to determine fault kinematics. Near-surface annual slip can be determined using various methods, such as the Global Navigation Satellite System (GNSS), Interferometric Synthetic Aperture Radar (InSAR), or geological studies. As a result of modeling using these methods, the slip amounts of the fault at any depth can be revealed. Interseismic modeling with the 3D Finite Element Model (FEM) is one of them. Considering the studies conducted in the literature, the effects of the discrete method of fault kinematics in the modeling performed with FEM have not been revealed. In order to fill this gap, 3D FEM modeling has been performed using velocity data from GNSS stations located around the Main Marmara Fault. The accuracy of the models made using different mesh types in ANSYS (Analysis System) software has been examined. The fault slip deficit values of the faults of the models with the lowest and highest Root Mean Square Error (RMSE) values have been compared. Possible earthquake magnitudes have been obtained after calculating the total slip deficit through taking into account the seismic gap. The moment magnitude of possible rupture difference has been revealed to be between 0.01 and 0.014 through using the lowest RMSE and the highest RMSE model.

Keywords

• finite element method
• mesh type
• GNSS
• modeling
• seismic potential