Seismic response of the Lengzhuguan slope during Kangding Ms5.8 earthquake

Abstract

In order to investigate the role of the amplification of peak ground acceleration (PGA) in seismic landslide formation mechanisms and study how earthquake waves interact with rock structures, a few strong-motion seismometers are installed at various locations on both sides of the Lengzhuguan gully. Five strong-motion seismometers were triggered at different depths in a tunnel at the same altitude during the Kangding Ms 5.8 earthquake on November 25th, 2014. The data reveal that the horizontal peak acceleration (PGAH) at each site decreased with increasing site depths. The PGAH at the deepest monitoring site (99 m from the tunnel entrance) was approximately half that of the outermost site. The amplitude of the acceleration response spectrum was also attenuated from the entrance inwards, the dynamic magnification factor (β) of the standard acceleration spectrum was less than 3.5, and rate of change was the same as that for the amplitude acceleration response. The Fourier spectra of each monitoring site also decreased from the outside inwards, and the components of the Fourier spectra were more complex at the surface.