The determination of radiated seismic energy of earthquakes based on regional seismic records

As a physical quantity describing the size of an earthquake, radiated seismic energy can provide an important reference for earthquake emergency and disaster assessment. Previously published methods to determine the radiated seismic energy often use broadband teleseismic records (35 degrees <=Delta<80 degrees). However, constrained by the correction for geometrical spreading and frequency-dependent attenuation, the determination of radiated seismic energy is more different for waveforms recorded at or near regional distances(5 <=Delta<35 degrees). In this paper, we generalize a method for energy estimation from teleseismic broadband records to the regional broadband waveform. The result can be concluded that: (1) We can obtain the radiated seismic energy of earthquakes above M(w)5.0 using this method, which makes up for the shortcomings that using teleseismic records can only stably determine the radiated seismic energy of earthquakes above My, 6.0 due to the influence of low signal-to-noise ratio and station distribution; (2) Applying this method to 66 earthquakes above Mw5. 0 occurred in mainland China between 2009 and 2021, the results show that the difference between corrected regional energy magnitude of a single station and the event can be controlled within 0.3 for 74% of the records; for 44 earthquakes with M-w >= 5.5, the average estimate of radiated seismic energy from regional data is nearly the same as that obtained from the teleseismic data, and the difference between corrected regional and teleseismic energy magnitude can be controlled within 0. 2 for 86% of the events; (3) Combined with seismic moment data, we investigate the characteristics of energy-to-moment ratio in mainland China. It can be concluded that the average energy-to-moment ratio is 2. 4/10 (5)(range, 5. 2x10 (6) similar to 8.1x10 (5)), the average energy-to-moment ratio of strike-slip earthquakes is higher than that of dip slip earthquakes. The distribution of energy-to-moment ratio has an overall regional characteristic. The average energy-to-moment ratio of earthquakes in the Xiyu region is higher than that in the eastern part of the Qinghai-Tibet Plateau region, while that in the western part of the QinghaiTibet Plateau region is the lowest. However, the wide variation of energy-to-moment ratios within the same region, on the other hand, suggests that there exist obvious differences in the energy release process of earthquakes on different faults; (4) The method remarkably shows a varied probability of applications. The radiated seismic energy can be determined in the daily work of the seismic network to provide new seismic parameters for scientific research, earthquake emergency response, and earthquake disaster assessment.