Examining the role of 3D nonlinear local site effects in the Canterbury earthquakes

Abstract

This research relates to the examination of 3D and nonlinear local site effects in the 2010-2011 Canterbury earthquake sequence. As part of understanding these effects a significant portion of research focused on the development of a Christchurch‐wide model for the characteristics of the shallow soils. The model that was developed comprises arguably the highest density of ground investigation information in the world. This work was undertaken by Postdoc Chris McGann.

A second package of work investigated in particular the 3D and nonlinear site effects at Heathcote Valley as a first case study in an ongoing program to examine such effects throughout the Christchurch region. Heathcote Valley is a natural choice to first examine these effects because of the fact the largest ground motions were consistently recorded at the HVSC station in the valley across most of the large magnitude events in the sequence. Such extreme ground motions were seen to be dominated by the inclined geometry of the Banks Peninsula volcanics in the shallow subsurface below the HVSC station which leads to significant surface wave generation. This work was undertaken by postdoc Seokho Jeong.

References for final report:

Journal papers:

1. McGann CR, Bradley BA, Cubrinovski M - Development of a regional Vs30 model and typical Vs profiles for Christchurch, New Zealand from CPT data and region-specific CPT-Vs correlation - Soil Dynamics and Earthquake Engineering, Vol 95, April 2017, Pages 48-60 - doi.org/10.1016/soildyn.2017.01.032
2. McGann CR, Bradley BA, Cubrinovski M - Investigation of shear wave velocity depty variability, site classification, and liquefaction vulnerability identification using near-surface Vs model of Christchurch, New Zealand - Soil Dynamics and Earthquake Engineering, Vol 92, January 2017, Pages 692-705 - doi: 10.1016/j.soildyn.2016.10.025

Conference papers:

1. Jeong S, Bradley BA - Simulation of systematic site amplification effects observed at Heathcote Valley during the 2010-2011 Canterbury Earthquake sequence - New Zealand Society for Earthquake Engineering conference - 20-12 April 2015, Rotorua, New Zealand, 9pp
2. Jeong S, Bradley BA, McGann CR, DePascale G - Characterization of dynamic soil properties and stratigraphy at Heathcote Valley, New Zealand, for simulation of 3D valley effects (poster) - Southern California Earthquake Centre (SCEC) Annual Meeting, 7-10 September 2014, Palm Springs, California, USA
3. McGann CR, Bradley BA, Cubrinovski M - A high-resolution shear wave velocity model for near-surface soils in Christchurch - New Zealand Society for Earthquake Engineering conference - 20-12 April 2015, Rotorua, New Zealand, 8pp
4. McGann CR, Bradley BA, Cubrinovski M - Ongoing development of a near-surface shear wave velocity model using Christchurch-specific empirical correlation between shear wave velocity and cone penetration test data - 12th Australia New Zealand confernece on Geomechanics, 22-25 February 2015, Wellington, New Zealand, Paper 46, 8pp