What is a tsunami?
A tsunami is a series of powerful waves with strong currents. They are mostly caused by underwater or coastal earthquakes and sometimes by underwater landslides or volcanic eruptions.
Learn more about Tsunami here.
Where do tsunami come from?
Tsunami can come from different sources.
A distant source tsunami, is most likely to be generated by a very large earthquake in the wider Pacific Ocean (i.e near the coasts of South America, Japan or off the west coast of USA) and could take at least 3 hours to arrive on New Zealand shores. A regional source tsunami, like one generated from the Kermadec Trench in the Southwest Pacific, could take between one and three hours to arrive. In both of these cases, the National Emergency Management Agency will likely have time to issue official warning messages.
A local source tsunami generated from an earthquake close to New Zealand. This type of tsunami is very dangerous because we may only have a few minutes warning before the wave arrives on our shores.
In this case, official warnings are unlikely to be issued before damaging waves arrive, so people in coastal areas need to take immediate action – if you feel an earthquake that makes it hard to stand or lasts more than a minute – move immediately to higher ground or as far inland as possible.
The three types of tsunami
There are three distinct types of tsunami. The type you encounter depends on the distance you are from the place where it is generated.
Tsunami Warnings
Warning messages and signals about a possible tsunami can come from several sources – natural, official or unofficial.
