Calculation of moment tensors of weak seismic events is challenging. Quite often we face a lack of stations and inaccurate velocity models. However information on moment tensors is important for understanding origin of the events (explosions, natural and induced earthquakes) and seismotectonic regime of the area. We re-analyzed two methods of retrieving moment tensors: (i) Inversion of amplitudes of P- and S-waves, and (ii) inversion of three-component full waveforms, complemented by first-motion polarities. The methods utilize different types of waves, different frequency bands, and different methods to calculate Green’s functions. We compare and discuss the methods in terms of reliability, efficiency and accuracy. The discussion is performed on examples of two weak earthquakes from Slovakian-Ukrainian border which appeared in April 2020, with local magnitudes 3.2 and 2.3.
To increase reliability of moment tensors of small seismic events, we analyze inversion of P- and S-wave amplitudes and three-component full waveforms. As example, we discuss two earthquakes from Slovakian-Ukrainian border from April 2020, with local magnitudes 3.2 and 2.3.