SLIDE - Stability of Land in Dynamic Environments

High altitude view of Wellington harbour and faultline. Credit Lloyd Homer

This project improves resilience of Wellington’s infrastructure through improving knowledge of the behaviour of anthropogenic slopes and developing strategies for more robust remediation approaches.


Stability of Land in Dynamic Environments (SLIDE) is a GNS Science research project that investigates the impact of landslides in Aotearoa New Zealand.

This project aims to

  • assess the performance of anthropogenic slopes in central Wellington under earthquake shaking, significant rain events, and a combination of both

To achieve these objectives, we will

  • provide stakeholders with new knowledge about the response of anthropogenic slopes to earthquakes and changes in groundwater
  • deliver best practice hazard and risk assessment methods to assess and quantify slope performance
  • recommend robust remediation approaches to infrastructure-critical slopes
SLIDE flowchartV2 toShow
SLIDE flowchart

The project

Anthropogenic slopes – a landslide hazard

Anthropogenic cut slopes and fill bodies are common throughout Aotearoa New Zealand. Between the early 1900s and 2019, there were more than 1,600 fill bodies and nearly 3,000 cut slopes formed within the central Wellington area alone.

Since the 1950s, larger scale earthworks – at the suburb scale – have been implemented. As a result, much infrastructure including lifelines (such as water, electricity, gas and telecommunications) are now sited on or below anthropogenically modified slopes.

These slopes are particularly susceptible to landslides, whether from earthquakes, rainfall or a combination of the two. The Stability of Land in Dynamic Environments (SLIDE) project, started in 2015, assesses the performance of anthropogenic slopes in central Wellington under earthquake shaking, significant rain events, and a combination of both. Currently, work is focused on landslide forecasting in future rain and earthquake events.

Early outcomes

At the beginning of the project, we conducted both regional- and site-specific investigations of landslides in the Wellington region. At the site-specific scale, we carried out ground investigations of select “infrastructure-critical slopes”. These investigations involved compiling historical datasets on past landslides, field mapping and the development of geomorphological maps for the central Wellington region, drilling/trenching, installing monitoring equipment and geophysical surveys.

We combined these regional-scale datasets to, for example, model the probability of a landslide occurring at a given location if subjected to 24-hour rain amounts equivalent to the 100- and 200-year return periods. We also modelled the probability of a landslide occurring at a given location if subjected to for example a 7.8 magnitude earthquake. The distance debris would travel downslope on large slopes was calculated, depending on whether it was a rain or earthquake induced landslide.

Landslide hazards were combined with infrastructure to determine the intersection of landslides and infrastructure in central Wellington. On a site-specific scale, once the properties of the selected slopes were determined, we built numerical models to simulate the response of these “infrastructure-critical slopes” under various loading conditions (e.g. earthquake and non-earthquake triggers).

Landslide model output SLIDE
Landslide model example

Key outcomes

The local (Wellington) regional-scale rainfall-induced landslide (RIL) hazard models developed by this programme are being upscaled so they can be applied nationally. The models are currently being incorporated into Geonet’s RIL forecast tool, to forecast landslide occurrence around New Zealand in response to near-real time rain forecasts. The Wellington RIL model will first be trialled across the Wellington region to forecast landslides in near real-time using NIWA rain forecasts.  

Hazard models and other information and knowledge generated by SLIDE are currently being used by national and regional organizations.

  • Toka Tū Ake EQC uses our research (via Riskscape) to assess the likely housing losses in Wellington from landslides triggered by rain and earthquakes.
  • Department of Conservation benefitted from the landslide risk assessment guidelines developed by this programme through the commission of a quantitative risk assessment of the Franz Josef and Fox Glacier valley, Westland.
  • The New Zealand Geotechnical Society intend to use the fill/cut slope design and risk assessment guidelines in their future geotechnical guidance modules.
  • The It’s Our Fault research programme is incorporating scientific data into councils’ preparation for landslide hazard and risk planning and will be largely underpinned by outputs from SLIDE’s earthquake-induced landslide models.
  • Publications

    Journal papers


    Failure mechanisms of Wellington fill slopes during earthquakes and rainstorms; J. Carey

    Literature review on the geotechnical properties of the Wellington region greywacke; M-A. Brideau

    Wellington rock slope characterisation and response to earthquakes; C.I. Massey

    Wellington regional scale landslide hazard models; C.I. Massey


    Cosgrove, B. 2018. Mechanisms of rainfall-induced landsliding in Wellington fill slopes. Victoria University of Wellington MSc thesis.

    Cosgrove, B.; Carey, J.M.; Norton, K. 2017 Mechanisms of rainfall-induced landsliding in Wellington fill-slopes. p. 23 IN: Baker, J.; Rowe, M. (eds) Geoscience Society of New Zealand Annual Conference 2017 : dynamic New Zealand, dynamic earth : University of Auckland, November 28 - December 1 : abstract volume. Wellington, N.Z.: Geoscience Society of New Zealand. Geoscience Society of New Zealand miscellaneous publication 147A.

    Massey, C.I.; Lukovic, B. 2018 A prototype earthquake-induced landslide forecast tool for New Zealand. p. 109-111 In: The abstract book of MEGE 2018 : the 5th International Symposium on Mega Earthquakes Induced Geo-disasters and Long Term Effects. Chengdu, China: State Key Laboratory of Geohazard Prevention and Geoenvironment Protection.


    GNS Science Reports

    SR2018/27 – SLIDE (Wellington): Vulnerability of dwellings to landslides; C.I. Massey

    SR2019/28 – SLIDE (Wellington): Geomorphological characterization of the Wellington urban area; D. Townsend

    SR2019/36 – SLIDE (Wellington): Development of an infrastructure model for analysing the potential impact of landslide in the Wellington Urban Area; D. Heron

    SR2019/37 – SLIDE (Wellington): Rainfall induced and earthquake induced landslide hazard models; C.I. Massey

    SR2019/38 – SLIDE (Wellington): Empirical and physics-based landslide runout models; S. deVilder

    SR2019/39 – SLIDE (Wellington): Review of Geomechanical Data for Greywacke in the Wellington Region;           M-A. Brideau

    SR2019/40 – SLIDE (Wellington): Geotechnical laboratory testing of Wellington Greywacke cores in unconfined compression; B. Lyndsell

    SR2019/41 – SLIDE (Wellington): Summary of borehole image and full-waveform acoustic processing and interpretation results; M. Lawrence

    SR2019/42 – SLIDE (Wellington): Methodology for quantitative landslide risk assessment; S. deVilder

    SR2019/43 – SLIDE (Wellington): Selection of representative ground motion input for the Wellington region; L. Abbott

    SR2019/44 – SLIDE (Wellington): Priscilla Crescent Site Specific Hazard and Risk Assessment; M-A. Brideau

    SR2019/45 – SLIDE (Wellington): Orchy Crescent Site Specific Hazard and Risk Assessment; M-A. Brideau

    SR2019/46 – SLIDE (Wellington): Dungarvan Road Site Specific Hazard and Risk Assessment; M-A. Brideau

    SR2019/47 – SLIDE (Wellington): Bendigo Grove Site Specific Hazard and Risk Assessment; C.I. Massey

    SR2019/48 – SLIDE (Wellington): Ngauranga Gorge Site Specific Hazard and Risk Assessment; C.I. Massey

    SR2019/49 – SLIDE (Wellington): St. Gerard Monastery Site Specific Hazard and Risk Assessment; C.I. Massey

    SR2019/50 – SLIDE (Wellington): A summary of the data, methods and assessments; C.I. Massey

    SR2019/51 – SLIDE (Wellington): Literature review of slope design guidance across NZ and internationally; F. Monteith

    SR2019/52 – SLIDE (Wellington): Risk remediation approaches for anthropogenically modified slope in Wellington region; F. Monteith

Research project details

Collaborators: Earthquake Commission (EQC), Wellington Water, New Zealand Lifelines Committee, Wellington City Council, New Zealand Transport Agency, MCDEM and regional CDEM groups, It’s Our Fault Programme



Funding platform

Hazards and Infrastructure - Targeted Research



Programme leader

Chris Massey



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