A Comparative Study on Seismic Intensity Evaluation Standards Based on Ground Motion Parameters:a Case Study of the Minxian-Zhangxian Ms6.6 Earthquake
With the accumulation of earthquake damage experience,the deepening understanding of earthquakes,and the development of seismic observation instruments,researchers have persistently pursued the continuous modification of intensity standards to make intensity evaluations more objec-tive and scientific. Ground motion parameters serve as a reference basis for assessing the seismic inten-sity of an earthquake and are an important component of seismic intensity scales. They are particularly effective in regions lacking certain seismic disaster discrimination phenomena. This paper processed and analyzed ground motion records obtained from the Minxian-Zhangxian Earthquake region and its surroundings to obtain horizontal,three-component synthetic ground motion parameters and seismic instrument intensity values. They study conducted seismic intensity evaluations based on horizontal ground motion parameters,three-component synthetic ground motion parameters,and seismic instru-ment intensity. It explored the influence of the three intensity evaluation methods on the results,veri-fying the consistency and differences between the current seismic intensity scale and the original inten-sity scale from the perspective of quantitative reference indicators of ground motion parameters. The results showed that:(1) The evaluation process based on three-component synthetic ground motion pa-rameters and seismic instrument intensity was more standardized,with results being more specific and accurate. (2) The intensity evaluation results based on three-component synthetic ground motion pa-rameters and seismic instrument intensity closely matched the actual macroseismic intensity,with 55％ of the evaluations differing by±1 degree and 91％ differing by±2 degrees. (3) The complete match rate improved by 18％ compared to the intensity evaluation results based on horizontal ground motion parameters. This research holds significant importance and practical value for more objective and scientific seismic intensity evaluations.
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