Preliminary Results from 3D Dynamic Earthquake Fracture Simulations in the Sea of Marmara


Korkusuz Öztürk Y.

Sunum, ss.1, 2018

  • Yayın Türü: Diğer Yayınlar / Sunum
  • Basım Tarihi: 2018
  • Sayfa Sayıları: ss.1
  • Erzincan Binali Yıldırım Üniversitesi Adresli: Evet

Özet

Locating at the western section of the North Anatolian Fault Zone, Marmara Region is a seismically very active area. The 1912 Mürefte and 1999 Izmit earthquakes are the last devastating events of the western and eastern sections of the region, respectively. The Center of the Sea of Marmara, the region between the epicentral locations of these two earthquakes, is prone to a large earthquake. Therefore, the analysis of the Central Marmara Sea is significant.

The main objective of our study is to determine 3D dynamic earthquake rupture scenarios, concerning non-planar and heterogeneous stress structures in the Sea of Marmara, using a Finite Element Model (FEM) via PyLith code. We use tetragonal meshes, so accuracies of the fault bends increase.

In this study, we first adapt test cases with heterogeneous stress patches based on the SCEC TPV205 case. Due the requirement of high computational demand, the most accurate cases are verified for the largest mesh size (300m) and the time step (0.02s) for planar (simple) and non-planar (complex) geometries. Analysis of non-planar geometries, especially with the increasing complexity of the model causes many errors and require a large number of iterations for the calculation parameters. Despite all, we concern the creeping and locked parts of the segments in the Sea of Marmara instead of assuming a homogeneous stress structure. Also, we try to adapt the most reliable frictional parameters with the help of results from the latest geodetic studies to decrease assumptions.

As a result, we expect to obtain the most reliable and accurate 3D dynamic earthquake rupture scenarios for the non-planar and heterogeneous fault structure in the Sea of Marmara. As a devastating earthquake is expected in center of the Sea of Marmara, the achievement of this modelling will contribute significantly to a better understanding of the fault movements of the area. Also, the results will make important contributions to the earthquake and tsunami early warning systems in the Marmara via presented rupture directivities.