On the correlation of ground motion parameters with slope stability incorporating topographic effects

Topography has complex effects on ground motions. In assessing seismic landslide stability， the proper ground motion parameters are needed considering the topographic effects on slope stability. Based on the strong ground motion accelerations of the main shock of Wenchuan M_S8.0 earthquake recorded by the Zigong topographic array， we analyzed the variation of peak ground acceleration (PGA)， Arias intensity and 95% significant duration against the terrain’s height， and discussed the correlation betweem the stability of slope during an earthquake and PAG/Arias intensity， with the topographic effect being taken into consideration. The following results are concluded. ① The amplification effect of topography on PGA and Arias intensity are both obvious. The amplification effect becomes generally stronger with the height of the terrain increasing, and the amplification effect is more obvious on horizontal ground motions than on the vertical component. For the horizontal ground motions， the amplification factors are between 1.1 and 1.8 for PGAs and between 1.2 and 3.3 for Arias intensity; the amplification coefficient are in the range from 1.1 to 1.3 and 1.2 to 1.7 for the vertical PGAs and Arias intensity， respectively. The discrepant amplification effect on PAG and Arias intensity shows the influence of topographic effects on strong motion is quite complex. ② The topography can also amplify the duration of strong ground motions， but there is slight difference in the amplification effect among records from different heights and for different components， with the amplification factors all being about 1.3. ③ Both Arias intensity and PGA can reflect the effects of topography on ground motions， and have strong correlations with the stability of slope. Compared with PGA， Arias intensity contains more information of the ground motions， and has a better capacity to capture the effects of topography on ground motions and on the potential seismic landslides hazard.