A tsunami is a long ocean wave (or series of waves) or surges, caused by a major disturbance to the sea floor such as an undersea earthquake, landslide or volcanic eruption. They are different to the storm tide surge which can occur with cyclones and from large waves which can accompany storms.

The phenomenon is usually associated with earthquakes, landslides or volcanic eruptions in, or adjacent to oceans, and results in sudden movement of the water column.

In deep water, tsunamis can reach speeds of up to 950km/hr and may travel across the sea for hundreds of kilometres, hitting distant communities hours after they are generated. They slow down but grow in size as they come ashore. Rather than one huge wave, a tsunami may look like a rapidly rising or falling tide and occur as a series of waves with periods of time in between. Despite the presence of the Great Barrier Reef, the Burdekin region could still be affected by a tsunami. Although the reef may reduce the impact of a tsunami, the scale of impact depends on what caused the tsunami, how far away the event is and where it is in relation to our shire.

TSUNAMI WARNING SIGNS:

  • You may notice changes such as the water withdrawing or becoming shallow.
  • A shaking of the ground in coastal regions may reflect the occurrence of a large undersea earthquake nearby that may generate a tsunami.
  • A roaring sound may precede the arrival of a tsunami.
  • A tsunami may not be one large wave approaching the coast. It can occur as a series of seemingly quite low but very powerful waves. The force of the water may be so strong it can carry vehicles, boats, bridges and buildings with it.

The difference between storm surges and tsunamis

  • Storm surges and tsunamis are generated by quite different phenomena. While both can cause inundation and significant damage in coastal regions, they have quite different characteristics.
  • A storm surge is generated by weather systems forcing water onshore over a generally limited stretch of coastline. It will normally build up over a few hours, as the cyclone or similar weather system approaches the coast.
  • Normally wind-waves on top of the surge will contribute to its impact.
  • A Tsunami is generated by earthquakes, undersea landslides, volcanic eruptions, explosions or meteorites. These travel great distances, sometimes across entire oceans affecting vast lengths of coastal land.

During a Tsunami

  • Tune into your local radio station and heed warnings and advice.
  • Follow local instructions and take immediate action, no matter how small the tsunami may be.
  • If you are at the beach, immediately move inland or to higher ground. Get out of the water and away from the coast.
  • If your boat is in deep water and offshore, maintain your position.
  • If your boat is berthed or in shallow water, secure your vessel and move inland or to higher ground.
  • If you are on the coast and cannot move inland, seek shelter in the upper levels of a stable building.
  • Stay where you are if your location is on high ground.

After a Tsunami

  • In an emergency dial 000 or 112 from a mobile.
  • Tune into your local radio station and heed warnings and advice.
  • Stay at your high ground location until advised it is safe to leave. More waves are likely to follow the first and it may take time for this to happen.
  • Beware of damaged power lines, roads, bridges and fallen trees.
  • Heed all warnings and don’t go sightseeing. Instead, check and offer help to neighbours, friends and family.
  • Turn off electricity, gas or water supplies and check whether they have been affected.
  • Wear rubber boots or rubber-soled shoes and rubber or leather gloves.
  • Check for cracks and damage to your building’s floors, walls and ceilings. Evacuate if the building is badly damaged.
  • Treat all items exposed to water as contaminated.
  • Dispose of rubbish, wash mud, dirt and debris as soon as you can.
  • Wash hands thoroughly after handling anything that has been in contact with water.
  • Follow any instructions for treating water. Conserve food and water as supplies may be interrupted.

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