Recurrent liquefaction in Christchurch, New Zealand, during the Canterbury earthquake sequence

Abstract

Continuous observational monitoring of a study site in eastern Christchurch, New Zealand, following the 2010 Mw 7.1 Darfield earthquake has recorded ten distinct liquefaction episodes in the mainshock-aftershock sequence. Three nearby accelerometers allow calibration between the geological expressions of liquefaction and the intensity of earthquake-induced surface ground motion at the site. Sand blow formation was generated by Mw 5.2-7.1 earthquakes with Mw 7.5-normalized peak ground accelerations (PGA7.5) of ≥ 0.057 g (acceleration due to gravity). Silt drapes between successive sand blow deposits provide markers for delineating distinct liquefaction-inducing earthquakes in the geologic rec..