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. Keywords: The 1998 Faial Earthquake,
Azores- North Atlantic, Stochastic finite-fault Ground Motion Simulation
method, Goodness of Fit Score