The Canterbury region of New Zealand experienced a sequence of significant earthquakes during 2010 and 2011. These earthquakes occurred on 2010-09-04, 2011-02-22, 2011-06-13 and 2011-12-23. Precise-levelling surveys have been carried out throughout Canterbury and Christchurch to re-establish heights after these earthquakes.
**Users may also be interested in the horizontal coordinates derived from GNSS data in the companion layers [Canterbury Earthquake Geodetic Marks (2010, 2011) - Comprehensive](http://data.linz.govt.nz/layer/1588) and [Canterbury Earthquake Geodetic Marks (2010, 2011) - Simple](http://data.linz.govt.nz/layer/1589)**
Horizontal Accuracy (standard deviation) approx 1m. Vertical Accuracy of Lyttelton Vertical Datum 1937 heights (standard deviation) 0.005m.
Heights generated from precise levelling data undertaken to a misclose standard (mm) of 5*sqrt(k) where k is the distance in kilometres. Precise levelling in the Christchurch area was undertaken after the 23 December 2011 earthquake. Other areas were levelled after the most recent earthquake to have affected heights in that area. Heights therefore represent the position of marks accounting for all four substantial Canterbury earthquakes.
These heights are only provisional. Analysis is ongoing as further data is collected. Heights calculated using SNAP v2.3.64. Heights were constrained using the pre-earthquake heights at geodetic codes AC9B, AFAQ, AG32 and B853. GNSS observations and modelling indicates that the height change of these marks was negligible. Some heights were calculated from precise levelling data provided by Christchurch City Council.
These coordinates are suitable for use in surveys and other geospatial activities in Canterbury and Christchurch.
**For further information about this dataset, see [the Canterbury earthquake information](http://www.linz.govt.nz/survey-titles/canterbury-earthquake/canterbury-earthquake/geodetic-survey-control-coordinates) on the LINZ website.**
To support the geospatial reference frame in post-earthquake Canterbury, including Christchurch.
Land Information New Zealand and the New Zealand Government.
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