Study On The Effect Of Site Condition To Ground Motion Amplitude And Attenuation Relations

Ground-motion attenuation relations are used for describing the change rules of the ground-motion parameters (amplitude, spectrum, duration) in spatial distribution. The relations translate the seismic wave generated from the focus (hypocenter) of earthquake to its induced ground motion in area where engineering projects are concerned. This paper analyses that site conditions affect to peak ground acceleration and effective peak acceleration based on plenty of practical strong ground motion data and provides the expression of the effective peak acceleration of each site condition. Meanwhile, this paper also studies the attenuation relations of different regions and different site condition. The study mainly comprises of 4 parts:1. 203 stations contained earthquake records in USA west are divided into four classifications based on site categories criteria of code for seismic design of buildings in China (GB 50011-2001). From these earthquake records, 1061 records are selected as the data base of the paper.2. When study the site condition affect to ground motion amplitude, the earthquake records are classified two direction of horizontal and vertical, and site conditions are allocated four classification ofâ… ,â…¡,â…¢andâ…£based on code for seismic design of buildings in China. The magnitude is allocated three classes, 4.5 to 5.5, 5.5 to 6.5, and 6.5 to 7.5. The epicenter distance is divided three classes, 0 to 30 km, 30 to 50 km, and 50 to 80 km. Study when the magnitude is fixed, the rules of peak ground acceleration variation with epicenter distance. And when the epicenter distance is fixed, the rules of peak ground acceleration change with magnitude. This paper also provides the definition of the effective peak acceleration of each site condition and the relationship of the peak ground acceleration and the effective peak acceleration.3. When study the attenuation relations of different regions and different site condition, this paper select the small-moderate earthquake recodes based on rock of four different regions (America, Japan, Europe, India)(4.0