Tsunami facts

• Tsunamis are not tidal waves, as they are not caused by tides and are not related to tides.
• They are generally triggered by a major earthquake under the ocean.
• Once created, they may propagate from the point of creation very fast (up to 435 mph)
• In the ocean, these waves may only be 0.5m high, but 50-60 miles wide.
• They may be so low and broad that they may not be recognized by ships.
• The first hit on land is usually not the biggest. Other larger waves may follow in 15-minute to one-hour intervals.
• As the waves enter coastal waters, their speed decreases and height increases.
• Coastal water usually recedes before the first tsunami strikes.
• Damage is generally caused by the flow of water (the run-up and drawdown) on the coastal area.
• Normally encounters look more like a quickly rising high tide than a large breaking wave.

What to do in the event of a tsunami

If a tsunami warning is given, never go to the beach to watch the wave come in because you will not live to tell the story! Rem ember that a tsunami is a series of waves and the first wave is not necessarily the biggest.

Before a tsunami

• If you live in a low-lying area, familiarize yourself with the quickest way to retreat to a safer location. Make sure all family members know the evacuation plan.
• If you are close to the sea and notice that the water recedes by an abnormal amount, move to safer ground at once. Do not stay to see what happens.
• Listen to the radio for official updates and instructions.
• Gather emergency supplies.
• Develop a family emergency plan.

After a tsunami

1. Avoid floodwaters. The water may be contaminated by oil, gasoline or raw sewerage. The water may also be electrically charged from downed power lines.
2. Avoid moving water. Moving waters only six inches deep can sweep you off your feet.
3. Stay away from downed power lines and report them to CUC.
4. Stay away from designated disaster areas unless authorities ask for volunteers.
5. Return home only when authorities indicate it is safe. Stay out of buildings surrounded by floodwater. Use extreme caution when entering buildings. There may be hidden damage, particularly in foundations.
6. Consider your family's health and safety needs:
   • Wash hands frequently with soap and clean water if you come in contact with floodwaters.
   • Throw away food that has come in contact with floodwaters.
   • Listen for news reports to learn whether the water supply is safe to drink.
   • Listen to news reports for information about where to get assistance for housing, clothing and food.
   • Seek necessary medical care at the nearest medical facility.
7. Service damaged septic tanks, cesspools, pits and leaching systems as soon as possible. Damaged sewerage systems are a serious health hazard.
8. Drain and clean cisterns as they may also be contaminated.