Near source ground-motion modelling of the Canterbury aftershocks and implications for engineering metrics

Anna E. Kaiser, & Caroline Holden

Published August 22, 2016, SCEC Contribution #6640, 2016 SCEC Annual Meeting Poster #287

The 2010-2011 Canterbury earthquake sequence includes the 22 February 2011 Christchurch aftershock (Mw 6.2), the June 2011 Mw 6.0 aftershock, the December 2011 magnitude (Ml) 5.8 and 6.0 aftershocks and the February 2016 Mw5.7 Valentine’s day earthquake. These events caused widespread liquefaction, rockfalls and heavy building damage and collapse.

Holden and Kaiser (2016) compute broadband synthetic seismograms for the largest M5.7+ aftershocks of the 2010-2011 Canterbury earthquake sequence at near-source sites. They 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. Their 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.

We propose to test the synthetic ground motion models of Holden and Kaiser (2016) against newly developed metrics by Rezaeian et al. (2015). These new metrics are ideally suited for the validation of ground motion models for structural and geotechnical engineering systems.

They consist of 3 time dependant metrics and 6 scalar parameters. Results from these tests are expected to bring new insights on the ground motion outputs in particular and valuable information on the modelling technique in general.

Key Words
ground motion simulation, validation, canterbury sequence

Citation
Kaiser, A. E., & Holden, C. (2016, 08). Near source ground-motion modelling of the Canterbury aftershocks and implications for engineering metrics. Poster Presentation at 2016 SCEC Annual Meeting.

Related Projects & Working Groups
Ground Motion Simulation Validation (GMSV)