Listen again to July 18th 2009 . The earthquake of July 16th caused only minor damage. One effect though, that scientists have learnt is that the southwest of the South Island has now moved 300mm closer to Australia.
New Zealand, like Japan, sits on the Pacific Ring of Fire which means that earthquakes can happen here. This earthquake happened where the Australia plate meets the Pacific plate. They press together with a lot of force.
Scientists used GPS, Global Positional System from a satellite, to see the changes to the land. Dunedin has moved only 10mm west and Te Anau has moved 100mm.