The whole South Island has been told to prepare for a massive earthquake in the near future. This is due to the Alpine Fault Line which is where the Australasian and Pacific plates meet on the West Coast of the South Island. The boundary between these two plates is locked and the pressure building up needs to be released. A release of such pressure would result in an earthquake about the size of a number 8 on the Mercalli Intensity scale. Such a earthquake would last for minutes, not seconds.
Canterbury University Associate Professor Tim Davies was quoted at a recent meeting as saying that, "The longer it goes before the next earthquake, the bigger the bang will be when the spring goes."
The shaking from the predicted earthquake would be felt all throughout New Zealand and may even be felt as far away as Sydney. Mr. Davies also emphasized that people should have food and supplies on hand to last for up to three weeks after a quake. Shaking damage and land instability from a quake like this would disrupt surface transport for months, tourists will be trapped, and distribution of vital supplies ( e.g. food, fuel) will be limited. Hydro stations will shut down immediately and may be slow to restart, power reticulation will be damaged. Only satellite phones will remain in use. Landslides into lakes and fiords may cause tsunami, as may the collapse of river deltas in lakes or the sea. Queenstown, Milford and Wanaka are likely sites of tsunami damage Tour bus operators are also urged to stock up on food and supplies for their customers who could likely be trapped for days in isolated locations.