Hancox, G.T.; Wright, K.C. 2005 Analysis of landsliding caused by the 15-17 February 2004 rainstorm in the Wanganui-Manawatu hill country, southern North Island, New Zealand . Lower Hutt: Institute of Geological & Nuclear Sciences. Institute of Geological & Nuclear Sciences science report 2005/11 64 p.
Abstract: The February 2004 rainstorm over the southern North Island caused extensive shallow landsliding over about 8000 km2 of Manawatu-Wanganui hill country. The Mangawhero Valley was the area most damaged by landsliding, the Whangaehu, Turakina, and Pohangina Valleys were also badly affected. This study describes and compares the terrain characteristics (topography, vegetation cover, rocks, soils, slope angle, slope height and slope aspect) and the nature of the landslides in four study areas in the Mangawhero, Whangaehu, Turakina, and Pohangina Valleys where extensive landsliding occurred. The nature of the landsliding in these four areas can be attributed to terrain characteristics, with the most important factors affecting landslide susceptibility and distribution being: slope angle, slope height and aspect, the nature of the underlying rocks and soils, and the type of vegetation cover present. Variations in rainfall intensity also appear to have strongly influenced the location and magnitude of the landslide damage. (auth)