1 Natural Hazards Classwork Classwork #1 Name: 4 th Grade PSI The Alps are the highest mountain range in Europe. They span eight different countries: Italy, Slovenia, Switzerland, Monaco, Liechtenstein, Germany, France and Austria. In the winter of , the Alps experienced 649 avalanches that killed over 265 people and caused extensive damage. This was the only time in history that this many avalanches hit the same area in such a short amount of time. This three month period has been named the Winter of Terror. An avalanche occurs when snow flows quickly down a mountainside. Avalanches can reach speeds of 80 mph within just 5 seconds! Avalanches occur when something causes the snowpack to crumble. When this happens, an entire slab of broken ice and snow will travel down a mountain as an avalanche. Most avalanches occur when the load (or weight) on top of the snow increases, causing the snowpack to break. The load on the snowpack can increase for many reasons: skiers, animals or even additional snowfall. Sometimes, gravity alone is enough to trigger an avalanche. Earthquakes can also cause snowpack to crumble into an avalanche. The Winter of Terror is thought to have been caused by an abnormal weather system. The Alps received high levels of precipitation combined with a polar cold front. This combination of factors caused the area to receive large amounts of snowfall in just a 2-3 day period. The accumulation of snow was very heavy and caused the snowpack to crumble, resulting in numerous avalanches.
2 1. Describe two ways that an avalanche could be triggered. 2. Wind is one factor that can cause an avalanche. Winter winds can push surface snow in one direction, causing it to pile up on top of snowpack. How could this trigger an avalanche? 3. Avalanches are most common in the 24 hours after a snow storm that deposits 12 inches or more of snow. Explain this statement.
3 Natural Hazards Homework Homework #1 Name: 4 th Grade PSI As a natural hazard, avalanches cannot be prevented. The damage caused by natural hazards, however, can be minimized. One of the dangers leading to avalanches is increased weight on top of the snowpack. The weight causes the snowpack to suddenly break. One way to prevent sudden avalanches is to trigger small avalanches when no people are around. Researchers dig holes and analyze the layers of snowpack. When they find a weak layer, they will trigger an avalanche by using explosives. This decreases the stress on the snowpack and helps to prevent future uncontrolled avalanches. Another method is to use structures to minimize the risk of an avalanche. A variety of different snow walls can be constructed to change the way that snow accumulates. This helps to minimize dangerous buildup of snow. Forests are a natural method of changing the accumulation of snow. The trees in a forest also slow down an avalanche, when one does form. In some cases, snow walls are constructed to slow down avalanches and to protect areas from damage. You are the owner of a renowned ski resort. The highlight of your resort is a steep ski slope that is incredibly challenging. Skiers come from all around the world to ski this particular slope. When you opened the resort, you clear cut the land of all trees in order to provide the most amazing view possible to your customers. It has come to your attention that the snowpack on the ski slope is compromised in several locations. The ski lodge, parking lot and main road are located at the bottom of the slope. If an avalanche
4 occurs, it will destroy all of your property as well as the lives of the people who travel to your resort. You have been urged to close the slope in order to address the issue before a deadly avalanche occurs. You are meeting with the authorities later in the week to present your avalanche management plan. Write your plan below. Be sure to explain each step of your plan.
5 Earthquakes Classwork Classwork #2 Name: 4 th Grade PSI Label each fault and describe the type of movement that occurs. 1. Fault: Movement: 2. Fault: Movement: Source: USGS 3. Fault: Movement:
6 4. Your brother comes home and tells you that earthquakes happen every time Earth s plates move. Is he correct? Why or why not?
7 Earthquakes Homework Name: Homework #2 4 th Grade PSI The chart below shows information from several earthquakes that have occurred between 1906 and Look at the information and then answer the questions that follow. Magnitude refers to the rating of the earthquake on the Richter scale. Rupture length refers to the length of the fault that moved. Magnitude Date Location Rupture Length Duration (kilometers) (seconds) 9.1 December 26, 2004 Sumatra, Indonesia January 9, 1857 Fort Tejon, CA May 12, 2008 Sichuan, China April 18, 1906 San Francisco, CA June 28, 1992 Landers, CA August 17, 1959 Hebgen Lake, MT October 17, 1989 Loma Prieta, CA October 28, 1983 Borah Peak, ID February 28, 2001 Nisqually, WA January 17, 1994 Northridge, CA March 10, 1933 Long Beach, CA October 1, 1987 Whittier Narrows, CA July 29, 2008 Chino Hills, CA 5 1 Source: Earthquakecountry.org 1. What earthquake had the largest rupture length? What was the magnitude of this earthquake? How long did the earthquake last?
8 2. What earthquake had the smallest rupture length? What was the magnitude of this earthquake? How long did the earthquake last? 3. Based on this information, how does rupture length relate to the magnitude of an earthquake? (Hint: As the rupture length of an earthquake increases, what happens to the magnitude?) 4. Based on this information, how does the rupture length relate to the duration of an earthquake? (Hint: As the rupture length of an earthquake increases, what happens to the duration?)
9 Volcanoes Classwork Classwork #3 Name: 4 th Grade PSI Categorize the following volcanoes as active, dormant or extinct. 1. Mount Etna in Italy has been erupting continuously for the past 3,500 years. 2. Meiji is the oldest island in the Hawaiian Islands. It is 85 million years old and no longer has a magma source. 3. Mount Kilimanjaro in Tanzania has not erupted in hundreds of thousands of years; however, there is still an active magma source running underneath the volcano. The statements below describe different ways that a volcano can form. Categorize each as convergent boundary, divergent boundary or hotspot. 4. Sometimes, magma pushes to the surface in areas not located by plate boundaries. 5. On the bottom of the ocean, some plates move apart from each other. Magma rises to the surface to create volcanoes.
10 6. When two plates collide, one plate pushes beneath the other. As the lower plate melts, magma sometimes rises to the surface and forms a volcano.
11 Volcanoes Homework Homework #3 Name: 4 th Grade PSI You are the newly elected mayor of Volcanoville, a small town that sits at the base of a large volcano. Your first task is to establish a Volcano Monitoring Program. You understand the risks of living directly beside a volcano. Although you cannot prevent the volcano from erupting, you want to be able to minimize casualties if it ever erupts in the future. Explain the steps of your monitoring program below. How is each step beneficial?
12 Tsunamis Classwork Classwork #4 Name: 4 th Grade PSI 1. Tsunamis are large ocean waves that can reach up to 30 meters high. Describe how tsunamis are linked to earthquakes. 2. What are two other ways that tsunamis can be created?
13 3. The picture below shows the DART buoy system. Describe the function of each labelled part
14 Tsunamis Homework Homework #4 Name: 4 th Grade PSI How Tsunami Science Has Advanced Since 2004 Tragedy The Indian Ocean tsunami of Dec. 26, 2004, was one of the worst natural disasters in history, killing 243,000 people in South Asia and East Africa with little to no warning. Ten years later, expanded networks of seismic monitors and ocean buoys are on the alert for the next killer wave. But hurdles remain in saving lives of everyone facing a tsunami threat. In 2004, tsunami waves approached coastal Indonesia just nine minutes after the massive magnitude-9.1 earthquake stopped shaking, said Mike Angove, head of the National Oceanic and Atmospheric Administration's tsunami program. Even today's expanded monitoring network can't issue an alert that quickly, "so we have to prepare the public to interpret the signs and survive," Angove said. When a tsunami wave rises, the alert comes from a $450 million warning network that was put in place after 2004's catastrophe. The Indian Ocean Tsunami Warning System includes more than 140 seismometers, about 100 sea-level gauges and several buoys that detect tsunamis. The global network of Deep-Ocean Assessment and Reporting of Tsunami buoys, which detects passing tsunami waves, has also expanded, from six DART buoys in 2004 to 60 buoys in 2014, Angove said. Getting the warnings to people living in remote coastal areas is one of the biggest hurdles for the new system. Another hurdle has to do with forecasting the effect of reflected tsunami waves. The
15 2004 Indian Ocean tsunami ricocheted off island chains, and some of the worst flooding arrived unexpectedly late in places like Sri Lanka and Western Australia. After an earthquake, scientists at NOAA's tsunami warning centers spend about an hour working out the details of a tsunami forecast, said Vasily Titov, director of NOAA's Center for Tsunami Research. The results project when the wave will arrive at shorelines and harbors, estimate tsunami-induced currents and gauge the height of the waves. The agency's goal is to dramatically reduce that hour of lag time. "We're now at the point where we want to do it in five minutes," Titov said. That means building out the seismic network, getting a faster response from sea-level sensors and speeding up the computer forecasts. "When these three components come together, then we can save everybody," Titov said. Becky Oskin, LiveScience Source: NBC News 2014, How Tsunami Science Has Advanced Since 2004 Tragedy, article, viewed on 30 June 2015, <
16 1. How have tsunami warning systems improved since the 2004 tsunami? 2. What is a weakness in current tsunami warning systems? 3. How long does it take scientists to interpret data to form a tsunami forecast? 4. What three things must become better in order to decrease the time it takes to form a tsunami forecast?
17 Answer Key Natural Hazards Classwork Classwork #1 1. Answers will vary but may include: increased load by skiers, animals or snowfall, explosives, gravity, or earthquakes. 2. When wind pushes snow to accumulate in one area, this increased weight can cause the snowpack to crumble. This can trigger an avalanche. 3. When there is a large accumulation of snow, the increased weight can cause the snowpack to crumble, triggering an avalanche. This is why avalanche danger is high in the 24 hours after a large snow storm. Natural Hazards Homework Homework #1 Answers will vary. Samples ideas: Plant trees to create forest surrounding the ski slope. This will help snow not to accumulate in one place and will slow down an avalanche if one does occur. Shut down the resort and use explosives to relieve stress in the snowpack. Create snow walls around the barriers of the ski slope to slow down an avalanche and to protect surrounding areas. Earthquakes Classwork Classwork #2 1. Strike-slip. Two rocks slip horizontally past each other. 2. Normal. One rock moves downwards. 3. Thrust. One rock moves upwards. 4. Your brother is wrong. Earth s plates are constantly in motion. Earthquakes occur when plates stop moving, store up energy and then suddenly release that energy. Earthquakes Homework Homework #2 1. The largest rupture length was Sumatra, Indonesia. The magnitude was 9.1 and the duration was 500 seconds. 2. The smallest rupture length was Chino Hills, CA. The magnitude was 5.4 and the duration was 1 second. 3. As rupture length increases, the magnitude increases. 4. As rupture length increases, the duration increases. Volcanoes Classwork Classwork #3 1. Active 2. Extinct 3. Dormant 4. Hot spot 5. Divergent boundary 6. Convergent boundary
18 Volcanoes Homework Homework #3 Answers will vary but should include seismic monitoring, gas monitoring and ground deformation monitoring. Tsunamis Classwork Classwork #4 1. When an underwater thrust earthquake forces a tectonic plate to move upwards, the column of water above the plate also is pushed upwards. This creates a wave (tsunami) that radiates out in all directions. 2. Tsunamis can also be created from underwater landslides or volcanoes This device detects seismic activity on the ocean floor. 2 This device detects changes in sea height. 3 This satellite receives signals from the other components and send the information to scientists. Tsunamis Homework Homework #4 1. In 2004, there were only 6 DART buoys. As of 2014, there were It takes scientists a long time to create a tsunami forecast. Sometimes, it takes longer to form the forecast than for the tsunami to hit land hour 4. Scientists was to increase the seismic network (increase DART sensors), get a faster response from the sea-level sensors and make computer forecasts run quicker.