ESOPA: a GUI-based MATLAB platform for estimation of earthquake spectral source parameters, inelastic attenuation, high-frequency decay kappa, and fmax-model

ESOPA-GUI, a MATLAB-based graphical user interface software, is presented in this study. The ESOPA-GUI estimates the seismic spectrum source parameters using Brune’s model (1970). The software uses two high-frequency decay models to represent the high-frequency decay of an event’s acceleration and displacement spectra: fmax-model and κ-model. The BODY-Q subprogram of ESOPA-GUI estimates and corrects the recorded time history corresponding to the loss of seismic energy by the wave propagation media. The software ESOPA-GUI has been applied to the data set of some earthquake of magnitude (MJ) 4.2 to 6.2, to estimate the spectral source parameters seismic moment (M0), moment magnitude (Mw), corner frequency (fc), stress drop (Δσ), source radius (r), fmax-model, and κ-model. The BODY-Q estimated the relationships Qβ = 26.68f1.01, Qβ = 31.56f0.96, and Qβ = 18.99f1.08 for different regions for Japan corresponding the data used, for the path correction. The solutions obtained using ESOPA are in good correlation with the solutions provided by popular agencies such as USGS and NIED which shows the reliability and stability of the software.