WHAT IS A TSUNAMI Imagine you’re standing on a beautiful beach Suddenly the ocean seems to be sucked back You can see fish flopping on the open ocean floor Then a giant wave builds and approaches the beach Watch out it’s a tsunami A tsunami is a series of huge ocean waves Each wave can reach 100 feet 30 5 m tall or more These waves can travel thousands of miles very quickly Sometimes they reach speeds of 500 miles 804 7 km DISASTER ALERT Some geologists believe an asteroid landing in the Indian Ocean caused a megatsunami or huge tsunami that hit Madagascar 10,000 years ago Waves could have been as high as 300 feet 91 4 km 4
Towns and cities on the coast are most at risk for deadly tsunamis per hour Tsunamis slam coastal towns and beaches sometimes causing great destruction They can sweep away trees buildings and even people and animals pulling them out to sea Where do tsunamis come from How can you stay safe before during and after a tsunami Let’s take a closer look at these killer waves 5
TSUNAMI TRIGGERS You’ve probably seen normal-sized waves at the beach They rise up and crash along the shore dragging pebbles and shells into the ocean These waves are usually caused by wind over the ocean In most cases they only travel at about 56 miles 90 km per hour These waves usually don’t cause damage Tsunamis happen when there’s a disturbance that causes water to be quickly displaced or moved Tsunamis may be caused by underwater landslides volcanic eruptions or most often earthquakes An earthquake in the middle of the ocean may drop or lift the ocean floor This movement makes the water rise and form a wave The wave may build and start to travel across the ocean toward the nearest coastline DISASTER ALERT 6 The word tsunami means great harbor wave in Japanese Japan is one of the places in the world that’s most affected by tsunamis
Normal ocean waves don’t pose too much of a risk to people Some people even surf on them 7
