Questions and Answers

Questions were posted by students on the Ask-an-Expert Web Board. The answers were provided by Shelley the LEARNZ Field Trip Teacher and Geospatial Experts.

All field trips have an Ask-an-Expert web discussion board for this purpose. The web board is now closed and a selection of questions and answers are shown here.

What is the purpose of maps to help the rebuild of Christchurch?

Maps are being used in lots of different ways to help the rebuild. Maps help record and show where damage to houses and services exists so people can be sent to the right places to make repairs. Maps have shown which roads are closed and where areas have been cordoned off.

Maps of peoples' properties have had information added to them; such as where water and sewage pipes are broken, where land levels have changed and where there have been rock falls. A map like this with more than one set of information on it is called a Geographic Information System (GIS). These maps have been used to help decide which areas should not be rebuilt on. Maps also show where land can be developed for new subdivisions. So without maps the Christchurch rebuild would be much harder and slower.
From Shelley the LEARNZ field trip teacher.

How many earthquakes have there been in Canterbury?

The Canterbury earthquakes sequence is still continuing and so far there have been well over ten thousand aftershocks since the first major shock on September 4 2010. Some are too small to feel and have not been recorded.
From Shelley the LEARNZ field trip teacher.

Why are there so many car parks in Christchurch and yet no buildings are going up?

The car parks are a use for open spaces that will eventually be built on or developed in some way. A lot of land is still being tested and analysed by geologists to make sure it is safe to build on. It is also not safe to start building when some buildings close by still need to be demolished. In some cases the land is soft and not well consolidated so special foundations have to be designed and tested - unfortunately all these things take time.
From Shelley the LEARNZ field trip teacher.

Why is it taking so long to rebuild Christchurch and why haven't they finished demolishing yet?

Yes this is a question that many people have been asking. The biggest problem is the scale of the damage. Many hundreds of buildings in the centre of town have been damaged beyond repair and demolishing them without harming undamaged buildings nearby is difficult and time consuming. Also Christchurch is still 'open for business' and it's impossible to close off large areas and demolish everything quickly. About 70 percent of the buildings in the Central Business District (CBD) have been, or will need to be, demolished.

Some buildings have only just been deemed unsafe as recent aftershocks have 'finished them off'. When you consider that one demolition could take nearly a year and then planning for a rebuild takes time too, you can see that it's certainly not an easy or quick job. The land also has to be drilled and analysed by geologists to make sure it is suitable for building on.
From Shelley the LEARNZ field trip teacher.