Physically based probabilistic seismic hazard analysis using broadband ground motion simulation: a case study for the Prince Islands Fault, Marmara Sea

Abstract

The main motivation for this study was the impending occurrence of a catastrophic earthquake along the Prince Island Fault (PIF) in the Marmara Sea and the disaster risk around the Marmara region, especially in Istanbul. This study provides the results of a physically based probabilistic seismic hazard analysis (PSHA) methodology, using broadband strong ground motion simulations, for sites within the Marmara region, Turkey, that may be vulnerable to possible large earthquakes throughout the PIF segments in the Marmara Sea. The methodology is called physically based because it depends on the physical processes of earthquake rupture and wave propagation to simulate earthquake ground motion time histories. We included the effects of all considerable-magnitude earthquakes. To generate the high-frequency (0.5-20 Hz) part of the broadband earthquake simulation, real, small-magnitude earthquakes recorded by a local seismic array were used as empirical Green's functions. For the frequencies below 0.5 Hz, the simulations were obtained by using synthetic Green's functions, which are synthetic seismograms calculated by an explicit 2D/3D elastic finite difference wave propagation routine. By using a range of rupture scenarios for all considerablemagnitude earthquakes throughout the PIF segments, we produced a hazard calculation for frequencies of 0.1-20 Hz. The physically based PSHA used here followed the same procedure as conventional PSHA, except that conventional PSHA utilizes point sources or a series of point sources to represent earthquakes, and this approach utilizes the full rupture of earthquakes along faults. Furthermore, conventional PSHA predicts ground motion parameters by using empirical attenuation relationships, whereas this approach calculates synthetic seismograms for all magnitudes of earthquakes to obtain ground motion parameters. PSHA results were produced for 2, 10, and 50 % hazards for all sites studied in the Marmara region.

Planar Seismic Source Characterization Models Developed for Probabilistic Seismic Hazard Assessment of Istanbul

“…A possible explanation for the separate ruptures in different episodes would be the development of the restraining bend along the Karadere segment, which probably locked up the eastern termination of Izmit rupture. Harris et al (2002) proposed that the rupture of 1999İzmit earthquake was stopped by a step-over at its eastern end (Mignan et al, 2015). In this study, we assumed the same rupture pattern of 1999 earthquakes and do not include a rupture scenario that combines these two rupture systems in the rupture forecast.…”

Active Probability Backpropagation Neural Network Model for Monthly Prediction of Probabilistic Seismic Hazard Analysis in Taiwan

“…From the geometrical mean of horizontal components of peak ground acceleration, peak ground velocity, and 5 % damped spectral acceleration in the 0.04 s -4 s period range. Reference [40] provided the results of a physically based (PSHA) methodology, using strong broadband ground motion simulations in sites within the Marmara region, Turkey. The physical processes of an earthquake rupture and wave propagation were necessary to simulate earthquake ground motion time histories for this methodology.…”

Evaluation of The Seismic Hazard in The Marmara Region (Turkey) Based on Updated Databases

“…Following the 1999 earthquakes, in addition to the several research efforts on source characterization in Marmara region, a number of studies were conducted for the estimation of future ground motions in the region. Probabilistic seismic hazard models were developed by [8][9][10][11] using different earthquake rupture models and forecasts together with various ground motion prediction equations (GMPEs), while [12][13][14][15] used physics-based simulations to estimate ground motion distributions from future fault ruptures. Spagnuolo et al [16] analysed the effects of the rupture directivity on the seismic hazard in Marmara region.…”