A Study On The Relationship Between Seismic Intensity And Spectral Accelerations Of Strong Motion

After an earthquake, strong motion observation network can get ground motion records at distributed strong motion stations. Based on these ground motion parameters, we can quickly determine the spatial distribution of seismic intensity, and then estimate the damage degree in different areas and the distrubtion of the extreme earthquake area, which provide the basis for the government to carry out emergency rescue and distribute forces and material rationally, to ensure that rescue workers reach the extreme earthquake area with search and rescue operations timely and accurately, and reduce the casualties and property loss. Therefore, this study focused on the determination of the intensity by the ground motion parameters, and carried out the research work as follows:1. We illustrated the necessity of rapid access to the intensity distribution using the ground motion parameters. We summarized the history of domestic and international work of rapid seismic intensity reporting and the emergency of a variety of analysis methods and quantitative relations, cleared the current research status and trend, and pointed out the importance to determine the seismic intensity by the earthquake parameters.2. We consolidated existing main strong motion records from the earthquake in China (Wenchuan earthquake, Ning'er earthquake, Yao'an earthquake, Yingjiang earthquake, Xinjiang earthquake and Panzhihua earthquake) and seismic intensity of field investigation data (the current intensity scale, historical seismic data, etc.). From the isoseismic maps obtained from the field survey after the earthquake, we pointed the corresponding intensity of the location of each station with ground motion record, and calculated the response spectrum by the acceleration data after baseline corrected based on the records of these stations.3. Based on the historical seismic intensity data and the strong ground motion records, and by multiple linear regression statistical analysis, we statically analyzed the corresponding relationship between the seismic intensity and the spectral accelerations at different periods. And we proposed two different methods, sub-area test and integrated test, to discriminate the seismic intensity using the spectral accelerations at different periods.4. We carried out Bayes hypothesis testing to the proposed methods in this study, and compared the estimated seismic intensity with the actual seismic intensity for Wenchuan earthquake. And the compared results show that our method can approximately reflect the true damage situation.Through the calculation, statistics and analysis, we provide understanding and conclusion to the research identifying the intensity from the ground motion parameters, providing a useful reference for seismic intensity rapid assessment.