Unit 4 Video Time Tsunami Killer Wave课件-2023-2024学年高中英语人教版（2019）必修第一册

Video Time Tsunami: Killer Wave Unit 4 Natural disasters 1.Watch the video to know about tsunami; 2.Talk about the safety instructions about tsunami; 3.Discuss on the relief work after tsunami. 2 What is tsunami? A tsunami is a series of ocean waves that sends surges (急剧上升) of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore. Lead-in Tsunami waves can strike out of nowhere and cause a lot of destruction. Scientists study and track tsunamis in order to warn people and minimize deaths. Tsunami: Killer waves What Causes a Tsunami? These waves are caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly, it displaces the water above it and launches the rolling waves that will become a tsunami. It may also be caused by underwater landslides or volcanic eruptions. Before you watch Task 1：Read the sentences about the formation and effects of tsunamis. Then match each sentence with the correct picture. A. Tectonic plates push together. B. A series of waves expands in all directions. C. Whole sections of cities are destroyed. While you watch A. Tectonic plates push together. B. A series of waves expands in all directions. C. Whole sections of cities are destroyed. Check your answers. A. Tectonic plates push together. B. A series of waves expands in all directions. C. Whole sections of cities are destroyed. Task 2： Watch the video again and decide whether the statements are true (T) or false (F). 1. There are few warning signs just before a tsunami hits. 2. A tsunami breaks just like an ordinary wave but is bigger. 3. Scientists at the Pacific Tsunami Warning Center monitor the earth’s movements 24 hours a day in order to track tsunami. T F T F T F Let’s watch the video again Check your answers. 1. There are few warning signs just before a tsunami hits. 2. A tsunami brea