Surveying earthquake damage to restore tourism

There has been extensive seismic activity in New Zealand over the last few years. In November there was another significant earthquake in the South Bay Marina, on the South Island.

The South Bay Marina and surrounding area in Kaikoura is a popular area for tourism and commercial fishing. However the earthquake has disrupted this activity with seabed uplift.

Areas that were previously channels for fishing or tourism boats to make their way into open water are now reduced to narrow passages, only usable at high tide.

Eliot Sinclair were approached to survey the damage after the earthquake and to re-establish chart datum.

 

 

GDA94 has updated to GDA2020

Don’t forget that the Geocentric Datum of Australia was adjusted on 1 January 2017.

This is to combat the movement of the tectonic plate on which Australia sits, more than 1.5m north-east since 1994. This movement creates discrepancies between local and global coordinates that are derived from GNSS.

Make sure that you are aware of the sources of your data, including the datum, to ensure you maintain your degree of precision.

The video below from Intergovernmental Committee on Surveying and Mapping’s (ICSM) explains the datum upgrade in more detail.

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Know the Sources of your Data

datumThe tectonic plate that Australia sits on is moving at a rate of 7cm to the north every year. This creates a discrepancy between local coordinates and global coordinates that are derived from GNSS. To address this the Geocentric Datum of Australia will be adjusted on 1 January 2017 by 1.8 meters to the north. This will bring local and global coordinates aligned in 2020.

As Joseph Kerski raises in his article, this “is a nice reminder that physical geography matters.” He reminds us to “know the sources of your data, including the datum itself.” An important reminder.

Read Joseph’s full article, or browse his blog.