A preliminary empirical model for frequency-dependent attenuation of Fourier amplitude spectra In Serbia from the Vrancea earthquakes

• Published in: Soil dynamics and earthquake engineering (1984) 2016-04, Vol.83, p.167-179
• Main Authors: Lee, V.W., Trifunac, M.D., Bulajić, B., Manić, M.
• Format: Article
• Language: English
• Subjects: Attenuation; Earthquake accelerograms; Earthquake engineering; Earthquakes; Estimates; Frequency dependent attenuation of strong motion from Vrancea earthquakes; Mathematical analysis; Mathematical models; Seismic wave energy; Spectra; Stress drop; Strong motion amplitudes at distances beyond 300; Testing of empirical equations via seismic moment
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/j.soildyn.2015.12.004

We present the frequency-dependent attenuation model for Fourier amplitude spectra of strong earthquake ground motion in Serbia from intermediate depth earthquakes in the Vrancea source zone in Romania. The development of this type of scaling is the essential first step toward developing the corresponding attenuation and scaling equations for pseudo relative velocity spectra (PSV), which are necessary for seismic macro- and microzoning in the territory of Serbia. Such scaling is necessary because the Vrancea source zone produces large earthquakes with shaking that attenuates differently from the local earthquakes in Serbia. Development of such a scaling model is associated with several difficulties, the principal one being the lack of recorded strong motion accelerograms at epicentral distances exceeding 300km. To reduce uncertainties with such scaling, we require our preliminary scaling equations to be consistent with independent estimates of seismic moment, stress drop, and radiated wave energy. In the future, when the recorded strong motion data from Vrancea earthquakes increases several-fold of what it is today, it will become possible to perform this analysis again, thus leading to more reliable and permanent scaling estimates. •Frequency dependent attenuation of strong motion from Vrancea earthquakes.•Extension of Yugoslav scaling equations for Fourier Spectra to Vrancea sources.•Scaling strong motion amplitudes at distances beyond 300km.•Tests of empirical Fourier Spectra at long and short periods and in terms of seismic energy.