Stochastic ground motion modelling of the largest M-w 5.9+aftershocks of the Canterbury 2010-2011 earthquake sequence

摘要

The 2010-2011 Canterbury earthquake sequence includes the 22 February 2011 Christchurch aftershock (M-w 6.2), the June 2011 M-w 6.0 aftershock and the December 2011 magnitude (ML) 5.8 and 6.0 aftershocks. These events caused widespread liquefaction, landslides and heavy building damage and collapse. To better understand the contributions of the source, path and site effects to these damaging ground motions, we compute broadband synthetic seismograms for the largest M-w 5.9 + aftershocks of the 2010-2011 Canterbury earthquake sequence at near-source sites. We employ a stochastic approach to compute the seismograms that is not only controlled by detailed source models but also by regional parameters derived using spectral inversion of the extensive Canterbury strong-motion dataset. Our results show that using appropriate stress drop value and site-specific amplification functions helps greatly to reproduce key engineering parameters such as peak ground accelerations (PGAs) and response spectra.