Determination of the seismic radiated energy of earthquakes with magnitude above 6.0 in the Tibetan Plateau of China

The seismic radiated energy is mainly carried by high-frequency body waves, which is directly related to the dynamic characteristics of the source. It can effectively make up for the lack of seismic moment and moment magnitude to describe the dynamic process and high-frequency components of the source, and provide a more comprehensive reference for earthquake emergency response and disaster assessment. In this paper, the radiated seismic energy of shallow earthquakes with moment magnitude above 6.0 has been measured in the Tibetan Plateau of China since 1990 by self-developed software, and the law of energy release has been preliminarily analyzed. The results show that: (1) Applying the method to 34 shallow earthquakes in the Tibetan Plateau of China, the results are stable and reliable. In general, the moment magnitude M_W and energy magnitude Me of an earthquake are not equal. In order to evaluate the seismic effect more comprehensively, it is necessary to consider not only the static characteristics of seismic fault dislocation, but also the dynamic characteristics of the source. (2) The energy magnitude of the Gaize earthquake and the Nima earthquake are 6.47 and 6.00, and the radiated seismic energy are 1.26×10¹⁴J and 2.54×10¹³J, respectively. The energy release of two earthquakes with similar source locations and the same moment magnitude can differ by as much as five times. The results of S transform show that the different dynamic processes of seismic source lead to the different process of radiated seismic energy release. Dynamic source parameters such as energy magnitude and radiated seismic energy are more suitable to describe the dynamic process of source and the potential damage of earthquake than moment magnitude. (3) Combined with the seismic moment data, the average energy to moment ratio of shallow earthquakes in the Tibetan Plateau of China is 1.9×10^-5, which is 1.6 times the global average. The energy to moment ratio is related to the focal mechanism and it is higher for the strike-slip earthquake than that of the dip-slip earthquakes. (4) The distribution of energy to moment ratio of the Tibetan Plateau of China has regional characteristic. The average energy to moment ratio in east and west is 2.25×10^-5 and 1.62×10^-5, respectively, and it is obviously higher in east than west. The regional difference of the energy moment ratio is related to the geological structure background. The radiated seismic energy can reflect the geological structure state in this area. The energy to moment ratios of earthquakes in the same region are also different. The energy moment ratios of shallow earthquakes in the Tibetan Plateau of China range from 5.03×10^-6 to 4.80×10^-5, which reflects the different energy release processes of earthquakes occurring on different faults. Therefore, it is necessary to measure the energy magnitude and moment magnitude together in order to reflect the source characteristics of the earthquake comprehensively.