Fast and Robust Earthquake Source Spectra and Moment Magnitudes from Envelope Inversion

With the present study we introduce a fast and robust method to calculate source displacement spectra of small earthquakes on local regional scale. The work is based publicly available Qopen full envelope inversion which further tuned for given purpose. Important parameters -- seismic moment, moment magnitude, corner frequency high-frequency fall-off are determined from by fitting simple earthquake model. demonstrated means data set comprising 2018 West Bohemia swarm. We report magnitudes, frequencies, centroid tensors inverted short period body waves with Grond package all magnitude larger than 1.8. Moment magnitudes calculated show very good agreement resulting probabilisitc tensor inversion. Furthermore, obtained multiple taper analysis direct onsets waves, but not affected large scatter second. moments scale frequencies according $M_0 \propto f_{\mathrm{c}}^{-4.7}$. Earthquakes result in smaller stress drop magnitudes. Self-similarity rupture observed. Additionally, frequency-dependent site amplification at used stations.