Earth Science Smartworks Activity Answers

1. Order events chronologically that can lead to a subduction-related tsunami. a. (first to last) The overriding plate “sticks” to the subducting slab, the overriding plate deforms and strain builds, slip occurs and the overriding plate moves back into position displacing a large amount of the seafloor, a bulge of water is created at the sea surface and spreads out as a series of waves 2. Rank historical tsunamis based on their associated fatalities. a. (highest to lowest) Indonesia 2004, Japan 2011, Alaska 1958, Greenland 1995 3. What type of motion does each mechanical seismometer record? a. 4. Arrange the following images from earliest to latest to model the formation of a new fault. a. (earliest to latest) 5. The news media often report an earthquake's magnitude on the Richter scale. Which of the following items are characteristics of a Richter earthquake magnitude? 6. 7. 8. 9. a. Represents the amount of energy released, determined from amplitude recorded by a single seismometer, uses a logarithmic scale The 2010 Mw 7.0 earthquake in Haiti caused an estimated 280,000 structures to collapse or sustain severe damage and resulted in the deaths of 100,000 to 160,000 people. However, a much larger Mw 8.8 earthquake in Chile that same year caused an estimated 550 deaths and significantly less damage to structures. Much of this difference in death toll and damage was due to the fact that Chile has strict building requirements, whereas no national building code exists in Haiti. What else can affect the number of deaths or amount of damage caused by an earthquake? a. Education of populace, distance from the earthquake, depth of the earthquake, type of material on which structures are built, magnitude of the earthquake This diagram shows the interior structure of the Earth. The inner core is shown as yellow, the outer core as orange, and the mantle as shades of purple. The yellow star marks the focus of an earthquake. Drag and drop the labels to show which type of seismic waves arrive at these three different locations as a result of the earthquake. a. Pink is both P-waves and S-waves, light purple is neither P-waves nor S-waves, dark purple is P-waves only Sort the following events by whether they occur before or during an earthquake. a. Before an Earthquake: elastic deformation accumulates, elastic deformation relaxes, rocks move up to a couple inches per year b. During an Earthquake: seismic waves are produced, rocks move up to 5,000 miles per hour, rocks “bounce” back and forth Based on the Tsunami Arrival topic of the Tsunami Initiation and Arrival Animation, order the events that take place as a tsunami approaches the shoreline. a. 10. Examine the three seismograms. They were recorded by three different stations during the same earthquake. They all have the same xaxis and y-axis scales. Based on what you have learned about wave amplitudes and S–P intervals, assign the seismograms relative distances to the epicenter using the labels to the right. a. (top to bottom) intermediate distance from epicenter, farthest from epicenter, closest to epicenter 11. Label the following images based on what type of earthquakeinduced disaster occurred. a. (top left, bottom left, top right, bottom right) Tsunami, sediment liquefaction, ground shaking and displacement, landslide 12. Four earthquakes were recorded on the seismogram below. Assuming they had the same epicenter, rank the earthquakes from strongest to weakest. a. (strongest to weakest) Earthquake B, Earthquake A, Earthquake C, Earthquake D 13. Analyze data from historical tsunamis to connect locations to the local cause of tsunami generation. a. Earthquake related: Lituya Bay Alaska, Japan, Indonesia b. Not earthquake: Greenland 14. Based on the Volcanic Eruptions topic of the Tsunami Initiation and Arrival Animation, select ways in which volcanic eruptions can cause tsunamis. a. Plausible: associated earthquake activity, volcanic structure collapse, water displacement by pyroclastic flows b. Unlikely: seawater expands as lava causes boiling