On The Computational Method Of Instrumental Seismic Intensity Based On Ground Motion Parameters

After earthquake event, spatial distribution of seismic intensity of the event and extremely destructed area could be quickly located by means of the empirical relationship, which has been proposed for years, between ground-motion parameters and seismic intensity. This can provide a basis for the government to carry out emergency relief and reasonable distribution of relief supplies. However, a question about using which ground motion parameter to calculate the instrumental seismic intensity will be more quickly and efficiently still haven't been solved. In this paper, further research were made on the two computational methods (One was proposed by the U.S. Geological Survey (USGS) and another one was proposed by the Japan Meteorological Agency) and a new method which takes the advantages of the two methods was initiated to determine the instrumental seismic intensity.The main research contents are as follow:1) The computational methods of the U.S. Geological Survey (USGS), Japan Meteorological Agency and of China were analyzed and introduced respectively. Meanwhile, the background, evolution process, calculation steps, advantages and disadvantages of those methods which were used to calculate the instrumental seismic intensity were clarified.2) The paper analyzed a large number of strong motion records, discussed whether or not to filter, and proposed filtering frequency range that suit to the site condition of China, and then discussed that which sort of acceleration should be choosed, the A0.3 which satisfies more than 0.3 seconds duration or the A_all which is synthesized by three components .3) We take the area where there have both the seismic intensity and strong ground-motion data to build the empirical formula of the A_all to seismic intensity and Vall to seismic intensity while the seismic intensity is between VI to VIII degrees.4) In this paper, we verified the seismic intensity of the empirical formula with the records of Wenchuan earthquake. The result shows that the method which was proposed by this paper is better that the other two methods which were mentioned above. Assume that±1 degree difference between the instrumental seismic intensity and seismic intensity is acceptable,the result of this method is acceptable at almost 100 percent. Further research about calculating instrumental seismic intensity was discussed and a new method for calculating instrumental seismic intensity was provided in this paper. We hope that this research can provide a useful reference to seismic intensity rapid assessment.