Rault, C. 2015 Quantifying the seismic response of slopes in Christchurch and Wellington : drillhole shear-wave velocity surveys, lithology and rock quality designation. Lower Hutt, N.Z.: GNS Science. GNS Science report 2014/54 60 p.
Abstract: This study presents results from drillholes and drillhole geophysical surveys carried out in the Port Hills of Christchurch. It presents the relationships between shear wave velocity (SWV), rock quality designation (RQD), and lithology type for the selected drillholes. The shear wave velocity for the rock materials in the Port Hills is mainly related to rock type and the depth below ground level (the overburden stress). For the basalt lavas there is a relationship between SWV and RQD, where the more intact the rock the higher the SWV. This is not true for the basalt lava breccias, where there appears to be no correlation with RQD, probably because the basalt lava breccia is not very dense and it contains lots of voids. However, for the basalt lava breccias there does appear to be a relationship between SWV and depth below ground level. For loess and colluvium, there is limited data, but SWV does not appear to correlate with depth, instead the SWV variability in the loess appears to be related to its moisture content. (auth)