The aim of using simulation techniques to provide generated ground motion data is to extend our knowledge on the effect of earthquakes and understanding their physical properties. Moreover, to fill the seismic gaps in case of insufficient recorded data in any region, ground motion simulations are widely used for earthquake engineering and seismology purposes. High-frequency accelerations have incoherent behavior because of unpredictable irregularities and heterogeneities associated with faulting and wave prpopagation. Simulations of ground motions frequencies beyond > 1 Hz can be represented with stochastic methods using simplified model representations of source, path and site effects. In this paper, stochastic simulations are performed for the recordings of the 26 September 2019 Silivri, Istanbul earthquake, using a finite fault simulation approach with a dynamic corner frequency. The main target is to create a valid synthetic model database with consistent source, path, and site parameters in the region that can be implemented in future simulation efforts. In calibration, we have used the recordings at 59 widely distributed stations in Istanbul located on different site conditions with epicentral distances ranging from 23 to 101 km. Four different frequency-dependent Q models were tested to obtain the best fit with the observations. By comparing generated ground motions to the observed ones, optimum source parameters and crustal characteristics were estimated. The calibrated model parameters have been obtained from the set of best-fit data with observed ground motion in frequency domain. Synthetic PGAs have been compared with the NGA-West2 Ground Motion Models (GMMs). Furthermore, spatial distributions of the ground motion intensity parameters were obtained and compared with available damage observations in Istanbul due to this earthquake. In conclusion, the results of the simulation were in good agreement with the recorded ones, both in time and frequency domains. The results indicate that the proposed stochastic model can be used to simulate ground motion distributions in Istanbul and beyond from past and future events in the region.

<p>One of the major earthquakes that resulted in intense damages in Istanbul and its neighborhoods took place on 10 July 1894. The 1894 earthquake resulted in 474 losses of life and 482 injuries. Around 21,000 dwellings were damaged, which is a number that corresponds to 1/7 of the total dwellings of the city at that time. Without any doubt, the exact loss of life was higher. Because of the censorship, the exact loss numbers remained unknown. There is still no consensus about its magnitude, epicentral location, and rupture of length. Even though the hardness of studying with historical records due to their uncertainties and discrepancies, researchers should enlighten the source parameters of the historical earthquakes to minimize the effect of future disasters especially for the cities located close to the most active fault lines as Istanbul. The main target of this study is to enlighten possible source properties of the 1894 earthquake with the help of observed damage distribution and stochastic ground motion simulations. In this paper, stochastic based ground motion scenarios will be performed for the 10 July 1894 Istanbul earthquake, using a finite fault simulation approach with a dynamic corner frequency and the results will be compared with our intensity map obtained from observed damage distributions. To do this, in the first step, obtained damage information from various sources has been presented, evaluated, and interpreted. Secondly, we prepared an intensity map associated with the 1894 earthquake based on macro-seismic information, and damage analysis and classification. For generating ground motions with a stochastic finite fault simulation approach, the EXSIM 2012 software has been used. Using EXSIM, several scenarios are modeled with different source, path, and site parameters. Initial source properties have been obtained from findings of our previous study on the simulation of the 26 September 2019 Silivri (Istanbul) earthquake with Mw 5.8. With the comparison of spatial distributions of the ground motion intensity parameters to the obtained damage and intensity maps, we estimate the optimum location and source parameters of the 1894 Earthquake.</p>