Research on prediction method of pulse type earthquake intensity based on improved JMA intensity
In order to solve the problems that the strong earthquake observation network was sparse in China,the pulse type earthquake records were few,and it was difficult to evaluate pulse type earthquake intensity in a certain area,a method to predict the pulse earthquake intensity was proposed.According to the historical earthquake situation,site condition and geological condition,impulsive earthquakes were generated through the utilization of artificial synthesis.The correlation between Japan Meteorological Agency(JMA)intensity and pulse type earthquakes was studied,and the JMA intensity method was modified by using the intensity filter of China seismic instrument.The intensity of 53 QQC station of Ludian earthquake was calculated by an example,and the intensity distribution cloud maps of Ludian earthquake and Wenchuan earthquake were drawn.Utilizing seismic stations from the Wenchuan earthquake,a comparative analysis was conducted between the improved JMA intensity calculation method and conventional intensity calculation methods.The results show that the high frequency components extracted from the historical seismic data are superimposed with the low frequency pulse components generated according to the site and geological conditions,and the artificial synthesis of pulsed ground motions can be realized.With the increasing of pulse speed,the JMA intensity exhibits an increasing trend.Regression analysis indicates a strong linear relationship between the logarithm of the pulse speed and JMA intensity.Simultaneously,as the pulse period progressively increases,JMA intensity shows an ascending trend.Regression analysis for pulse period and JMA intensity also reveals a linear relationship.It is evident that JMA intensity is closely related to pulse seismic and can be utilized for measuring pulse ground motion intensity.In comparison to the original filter,the improved filter features a significantly wider effective bandwidth.The effective frequency band is between 0.3-3 Hz,which can cover the excellent frequency of most engineering structures in China.Internally,it demonstrates a more uniform response within the effective bandwidth,while the external effective bandwidth displays a steeper response,resembling characteristics closer to an ideal filter.
instrumental intensityband-pass filterpulse type earthquakeearthquake intensityground motion synthesis
NETL
NSTL
万方数据
