# The ground that moves

The district plan’s slope-hazard management areas, 631 mapped areas covering 93,759 hectares where the Port Hills are watched for rockfall, cliff collapse and mass movement, drawn from the post-earthquake geotechnical review. A management overlay, not a prediction.

## The bands

- Cliff Collapse Management Area 1: 4 areas, 12 ha
- Cliff Collapse Management Area 2: 51 areas, 34 ha
- Mass Movement Management Area 1: 9 areas, 14 ha
- Mass Movement Management Area 2: 19 areas, 34 ha
- Mass Movement Management Area 3: 12 areas, 7 ha
- Rockfall Management Area 1: 171 areas, 1,168 ha
- Rockfall Management Area 2: 348 areas, 231 ha
- Remaining Slope Instability Management Area: 17 areas, 92,260 ha

## The suburbs on the watch
By share of outline under the named bands (rockfall, cliff collapse, mass movement), a sampled join, so a sliver still counts.

- Heathcote Valley: 37% under named bands, inside the broad instability overlay too
- Lyttelton: 26% under named bands, inside the broad instability overlay too
- Corsair Bay: 22% under named bands, inside the broad instability overlay too
- Cass Bay: 21% under named bands, inside the broad instability overlay too
- Cashmere: 14% under named bands, inside the broad instability overlay too
- Redcliffs: 14% under named bands, inside the broad instability overlay too
- Clifton: 14% under named bands, inside the broad instability overlay too
- Hillsborough: 10% under named bands, inside the broad instability overlay too
- Te Onepoto Taylors Mistake: 10% under named bands, inside the broad instability overlay too
- Sumner: 10% under named bands, inside the broad instability overlay too
- Scarborough: 9% under named bands, inside the broad instability overlay too
- Moncks Bay: 7% under named bands, inside the broad instability overlay too
- Governors Bay: 6% under named bands, inside the broad instability overlay too
- Kennedys Bush: 4% under named bands, inside the broad instability overlay too
- Saint Martins: 4% under named bands, inside the broad instability overlay too

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Christchurch City Council open data, the DistrictPlanB service’s DPSlopeHazard layer, the operative plan’s slope-hazard management areas. A consent overlay, not a prediction: ground outside the line is not certified stable. A point’s own answer: https://www.chch.live/before · the rocks that already fell: https://www.chch.live/boulders · the sea’s reach: https://www.chch.live/tsunami. The files: https://www.chch.live/slope.json · https://www.chch.live/slope.geojson · by suburb: https://www.chch.live/suburb-slope.json