Characteristics of ground motion records in Zigong mountain array during “5.12” Wenchuan Earthquake

Based on the strong ground motion data recorded at Zigong array during Wenchuan Earthquake on May 12, 2008, the characteristics of peak ground acceleration (PGA) and response spectrum are analyzed. The results indicate that the mountain topography greatly influences the seismic wave propagations. The horizontal PGA increases more greatly than the vertical PGA with increasing elevation of the mountain; however this increase is not monotonous and related to the features of local mountain topography. The influences of topography on acceleration response spectra mainly depend on the source frequency content. The high frequency content beyond 1 Hz of seismic waves has been amplified more greatly. And the results also indicate that the displace response spectra are almost uninfluenced by the mountain topography.