Stochastic ground motion simulation of the 9th of July 1998 Faial earthquake (Azores, North Atlantic)

Abstract

Earthquakes are among the most destructive natural disasters, resulting in a huge number of fatalities and economic losses all over the world. For regions with limited number of seismic networks or for regions where there is a seismic gap to produce large magnitude and destructive earthquakes, ground motion simulation approaches provide alternative region-specific time histories for potential events. Region-specific simulations require modeling and calibration of input parameters in terms of source, path and site effects. Verification of these parameters is a challenging task and can be accomplished through comparing the real time histories of the past events against the simulated data. In this study, the recorded time histories of the 9th of July 1998 Faial earthquake (Mw=6.2) at available stations are simulated with the stochastic finite-fault ground motion simulation approach based on a dynamic corner frequency concept. For ground motion simulations, alternative region-specific source, path and site models are employed and tested. The best model is proposed through goodness of fit score which is evaluated through the complementary error function in terms of various seismological parameters between the real and simulated record sets. These seismological parameters include peak ground acceleration peak ground velocity, the ratio of peak ground velocity to peak ground acceleration, Arias intensity, cumulative absolute velocity, acceleration spectrum intensity, modified acceleration spectrum intensity for the period range of 0.1 to 2.5 seconds, velocity spectrum intensity, Housner intensity, significant duration, bracketed duration, Fourier amplitude spectra within the frequency range of 0.1 to 25 Hz and pseudo response spectra within the period range of 0 to 4 seconds. The simulation results demonstrate that for the event of interest the input parameters are verified, and the fits between the real and simulated time histories are satisfactory.