Rapid evaluation of radiated seismic energy for great shallow earthquakes from 2014 to 2019
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Graphical Abstract
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Abstract
Based on seismic waves’ attenuation characteristics and the one-dimensional velocity model, we conducted a study for the rapid determination of radiated seismic energy ES and energy magnitude Me. The seismic recordings obtained from the Global Seismographic Network and China Seismological Digital Network were used to calculate the ES and Me of 115 shallow earthquakes with MW≥6.0 from 2014 to 2019, and the results were compared with MW and Me produced by other institutions. The results show the stable Me can be obtained within half an hour after obtaining the seismic data, and the Me values of IRIS were consistent with the earthquakes analyzed in this study. The earthquake damage is closely related to the size of energy magnitude Me, and the devastation that an earthquake can cause is more serious when the energy magnitude Me is far greater than the moment magnitude MW. In all types of earthquakes, the efficiency of radiated energy for earthquakes with strike-slip faults is high, with Me being significantly greater than MW. Next, by analyzing two MW6.1 earthquakes occurred in Hualien, Taiwan region on February 4, 2018 and April 18, 2019, it is concluded that two earthquakes with the same source mechanism in similar locations, although they have the same moment magnitude MW, the energy magnitude Me vary greatly, close to 0.5. MW can only obtain the source’s static characteristic, which is closely related to the static tectonic effects such as fault area and average dislocation of rupture caused by earthquakes. In contrast, Me can provide the source’s dynamic information and objectively evaluate the damage intensity of an earthquake. Therefore, the approach applied in this study can ensure the accuracy of the results and greatly improve the measurement speed of energy magnitude Me, which is very suitable for a rapid response system. Our research results can provide a reference for the future seismic network to take energy magnitude Me as daily output magnitude and provide more information for rapid assessment of disasters caused by large earthquakes.
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