Source Spectra for Global Shallow Large Earthquakes from 2000 to 2024

The kinematic characteristics of an earthquake source offer insights into its physical properties, with macroscopic parameters such as seismic moment and radiated energy serving as key indicators for describing seismic hazards. In this study, we explored the characteristics of earthquake sources in the frequency domain. Specifically, we introduced a hybrid method using teleseismic P-wave data to derive source spectra for over 200 large (M_W > 7) shallow (depth < 70 km) earthquakes from 2000 to 2024. Our analysis reveals that in a simple ω^-n model, the power exponent n is consistently less than 2 when the corner frequency aligns with the earthquake's total duration. To further characterize earthquake source properties, we defined the centroid frequency (f_e) as the centroid of the energy spectral density which can represent the dimension of asperities on the fault plane. We also proposed the ratio between observed radiated energy and that predicted by the ω^-² decay model as a metric for quantifying rupture heterogeneity (R_H). Relationships of f_e and R_H with focal mechanism, magnitude, and centroid depth were analyzed within the conventional asperity model framework. Our source spectra dataset can also provide a robust foundation for future investigations into earthquake sources.