The UN General Assembly has called on the world to mark World Tsunami Awareness Day this Saturday, November 5.
New Zealand’s entire coastline is at risk of a tsunami and it’s a risk everyone needs to take seriously. Warning messages and signals about a possible tsunami can come from several sources; natural, official or unofficial. For a local source tsunami that could arrive in minutes, there won’t be time for an official warning so it’s vital that people can recognise the natural warning signs and act quickly.
Bay of Plenty Regional Council therefore encourages people to use this Saturday, November 5 as an opportunity to read up about the hazards Bay of Plenty is exposed too, make a plan and put it into practice as a family. It's worth finding out where the nearest evacuation routes and meeting points are and identify the closest area of higher ground.
· A tsunami is a series of fast-travelling waves caused by a large disturbance in the sea or on the ocean floor, such as an earthquake, landslide, volcanic eruption or meteorite. The waves can be an hour apart, and can travel many thousands of kilometres across the oceans at great speeds of up to 800 kilometres per hour.
· A tsunami may go unnoticed as it crosses deep oceans, but it loses speed and gains height when it reaches shallow water. Large waves up to 15 metres or more in height can come crashing onto the land.
· Even small tsunami waves can be dangerous, causing unusually strong currents and unpredictable water flows near the shore. This means a threat to beach, harbour, estuary and small boat activities.
· In the past 200 years, there have been at least three tsunami that were more than 10m high at the New Zealand coast. Māori mythology also speaks of large tsunami. Some were caused by distant earthquakes, some by underwater quakes not far off the coast.