Slide 1 / 142 Slide 2 / 142 4th Grade Natural Hazards 2015-11-18 www.njctl.org Slide 3 / 142 Slide 4 / 142 Table of Contents Click on the topic to go to that section · Natural Hazards Natural Hazards · Earthquakes Volcanoes · · Tsunamis Minimizing Damage · Works Cited · Return to Table of Contents Slide 5 / 142 Slide 6 / 142 What happened? What happened? Look at the picture below. How many different ideas can you This is the result of an earthquake that hit Haiti in 2010. brainstorm about what may have destroyed this area? Source: Wikimedia Commons. Author: Abassi. Source: Wikimedia Commons. Author: Abassi. An earthquake is an example of a natural hazard. The next slides describe a different natural hazard that hit Alaska in the 1950s. Pay attention and see if you can come up with a definition for natural hazard.
Slide 7 / 142 Slide 8 / 142 Lituya Bay, Alaska Lituya Bay, Alaska Lituya Bay is part of the Glacier Bay National Park and Preserve.The Lituya Bay is a fjord located on the coast of Alaska. It is 14.5 km long and 3.2 km wide. Cascade Glacier, the Crillon Glacier and the Lituya Glacier all feed into Lituya Bay. Cenotaph Island is located in the middle of the bay. L i t u y a G r e l i a c a c l G i e e r d a c s a A fjord is a narrow, deep C inlet that runs between Crillon Glacier high cliffs. Cenotaph Island Source: Wikimedia Commons. Author: Nzeemin. Source: Chadron State College. Author: U.S. Geologic Survey. Slide 9 / 142 Slide 10 / 142 1953 - Lituya Bay 1953 - Lituya Bay In 1953, scientists visiting Lituya Bay found evidence of immense What evidence of destruction did the scientists discover? destruction around the bay. Mature trees did not extend all the way down to the water, as it did in Click here to watch a video about the 1953 Lituya Bay event. neighboring areas. Much younger trees were located by the water. What is a trim line? The place where trees of different ages meet. What information did the Juno Forestry Research Lab provide? The tree rings showed that a violent force struck the forest. Possibly a giant wave. Source: National Park Service After watching the video, move to the next slide to answer questions. Questions continue on next slide. Slide 11 / 142 Slide 12 / 142 1958 - Lituya Bay 1953 - Lituya Bay Five years later, a similar event happened. This time, however, the Why was this information confusing for the scientists? event was documented and had a few witnesses. In order for a wave to reach that high in the forest, it would have had Click here to listen to an eye witness acount of the event. to be 150 meters tall. A wave this high had never been recorded Rockslide before. It seemed impossible. An earthquake caused a rockslide. Over 30 The scientists were unable to make any sense of this information million cubic meters of and they left the area puzzled. As a class, come up with a rock fell into the bay hypothesis about what happened. Write it below. from a height of 914 meters. The force of the rocks hitting the water created a mega tsunami that travelled through the bay. Source: Chadron State College. Author: U.S. Geologic Survey.
Slide 13 / 142 Slide 14 / 142 1958 - Lituya Bay Natural Hazards This image shows the coastline of the bay. The lighter area is where What happened at Lituya Bay is an example of a natural hazard. A the wave uprooted and destroyed all trees. natural hazard is any extreme event that occurs from natural processes. Was there anything that could have been done to prevent the natural The wave removed hazard in Lituya Bay in 1958? Write any ideas below. vegetation as high as 524 meters (1720 feet) above the waterline. It is the largest wave ever recorded. Source: Wikimedia Commons. Author: Miller. Slide 15 / 142 Slide 16 / 142 Natural Hazards Natural Hazards In this unit, we will examine natural hazards that are a result of Natural hazards cannot be prevented. However, by analyzing plate tectonics. Think back to the first unit of the year. What are natural hazards, we can attempt to minimize the damage that they plate tectonics and plate boundaries? cause. Click here to watch a video of how scientists have analyzed the Lituya Bay mega tsunami. Tectonic plates are pieces of the Earth's crust. Where tectonic plates come together and interact is called a plate boundary. What did scientists learn about the wavelengths of mega tsunamis compared to storm waves? Natural hazards from activity at plate boundaries include: The wavelengths of mega tsunamis are incredibly large. This enables them to create a massive wave as it approaches shore and to engulf the land, causing immense destruction. Source: Wikimedia Commons. Author: McGimsey. Source: Wikimedia Commons. Author: Tubbi. Source: Wikimedia Commons. Author: Harriv. Volcanoes Earthquakes Tsunamis Slide 17 / 142 Slide 17 (Answer) / 142 1 What initiated the destruction in Lituya Bay? 1 What initiated the destruction in Lituya Bay? A Hurricane A Hurricane B Rockslide B Rockslide Answer C Earthquake C Earthquake C D It is unknown. D It is unknown. [This object is a pull tab]
Slide 18 / 142 Slide 18 (Answer) / 142 2 A natural hazard is any extreme event caused from 2 A natural hazard is any extreme event caused from natural processes. natural processes. True True False False Answer True [This object is a pull tab] Slide 19 / 142 Slide 19 (Answer) / 142 3 Natural hazards can be prevented. 3 Natural hazards can be prevented. True True False False False Answer Natural hazards CANNOT be prevented but damage from them can be minimized. [This object is a pull tab] Slide 20 / 142 Slide 21 / 142 Plate Tectonics Remember that Earth's crust is composed of several different pieces that fit together like a puzzle. Earthquakes Source: Wikimedia Commons. Author: U.S. Geological Survey. Return to The plates are constantly moving in relation to each other. Table of Contents
Slide 22 / 142 Slide 23 / 142 Faults Faults There are a few different ways that rocks can move in relation to There are areas in the Earth's crust where two plates rub against each other. each other. These are called faults. In how many different ways can you imagine that plates rub against each other? Write your ideas below. Two rocks can move horizontally beside each other (strike-slip fault). Click here to watch a strike-slip fault animation. A rock can be moved downwards (normal fault). Click here to watch a normal fault animation. A rock can be pushed upwards (thrust fault). Source: Wikimedia Commons. Click here to watch a thrust fault animation. Author: U.S. Geological Survey. Slide 24 / 142 Slide 24 (Answer) / 142 Energy Review Energy Review Think back to your unit on energy. Think back to your unit on energy. Imagine that you compress this spring so that all the coils are Imagine that you compress this spring so that all the coils are touching each other. What will have more energy: the touching each other. What will have more energy: the uncompressed spring or the compressed spring? uncompressed spring or the compressed spring? The compressed spring will have more energy. Answer The compressed spring contains potential energy. When you release the spring, the potential energy changes into kinetic energy. Source: Wikimedia Commons. Author: Milan. Source: Wikimedia Commons. Author: Milan. What type of energy does the compressed spring have? If you What type of energy does the compressed spring have? If you [This object is a pull tab] suddenly let go of the spring, what type of energy does it have suddenly let go of the spring, what type of energy does it have now? now? Slide 25 / 142 Slide 26 / 142 Plates Can Store Energy Plates Can Release Energy Sometimes, the sides of plates are not completely smooth. They Eventually, there is so much force being applied to the plates that have bumps and irregularities that cause them to get stuck, or they become unstuck and quickly move past each other. locked, in place when they should be moving past each other. Although the plates are no longer moving, the same amount of force The potential energy is suddenly released as what type of is being applied to them. energy? When plates stop moving, what type of energy is being stored at the Kinetic energy fault? Potential energy It is this sudden release of energy that is felt as an earthquake. This fault in France shows one side being This picture shows a strike slip pushed downwards while the other side fault in the Taklamakan Desert moves upwards. in China. Source: Wikimedia Commons. Author: NASA Earth Observatory. Source: Wikimedia Commons. Author: Xhienne.
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