Surveying through the Christchurch Earthquakes

The recent series of earthquakes in Canterbury grossly affected thousands of survey marks, essentially destroying the physical control survey network. Long established reference marks including geodetic, cadastral, and height bench marks became ‘disturbed’, as extensive random ground movement rendered them unreliable.

Canterbury’s dynamic environment meant marks continued to move for many months as the ground refused to settle. To work in such an environment it became clear that traditional terrestrial methods would not suffice. GNSS technologies would become essential on virtually every job.

Our CORS  at Wigram experienced virtually no movement throughout the quakes, underpinning our ability to continue with accurate and repeatable surveys. This enabled us to respond immediately with a global ‘monitoring style’ solution when the integrity of ground marks was questionable, allowing us to determine the magnitude of movement of the stability of any mark.

The article below focuses on Eliot Sinclair’s adaption to post-quake surveying in Canterbury, utilising permanent reference stations for real-time GNSS corrections.

To view the full article please see the link below.

 

48x48-pdfArticle: Surveying through the Christchurch EarthquakesThis article first appeared in the NZIS publication Survey December 2013: Issue 76 

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