Investigation 3: Predicting Eruptions

Transcription

1 Investigation 3: Predicting Eruptions Table of Contents Folder 1: Seismic Activity Folder 2: Ground Deformation (Mount St. Helens, Washington) Folder 3: Hot Spots Folder 4: Gas Emissions Folder 5: Summary Going Further: USGS Hazards Program Going Further: Gas Plumes CE3 T eacher s G uide - Module 1 Page 22

2 Folder 1: Seismic Activity Scientists can listen to movements below ground to help predict when a volcano might erupt. Step Complete 1. Open and read the Introduction placemark balloon. 2. Expand Folder 1: Seismic Activity and click on the radio button. Open the Mount Rainier, Washington placemark balloon. Read the information and record any observations you can. Then close the balloon. 3. Turn on the Seismic Monitoring folder to see all the seismograph stations around Mt. Rainier. Fortunately, computers can help interpret all the signals from these stations. Record your observations. Observations What is an active volcano? What is an extinct volcano? What is a dormant volcano? What is seismic activity? What underground events can seismographs record? What aboveground events can seismographs record? What is a seismic signature? CE3 T eacher s G uide - Module 1 Page 23

3 How does the seismic signature of an earthquake occurring near Mt. Rainier compare with that of a distant earthquake? Number of active volcanoes shown on the Seismic Monitoring overlay: Approximate number of seismic stations shown on the overlay (over 10, over 100; over 1000): How do scientists interpret the seismograph signals from so many seismograph stations? Interpretation Can seismographs help scientists determine whether a volcano is about to erupt? Claim: Evidence: Reasoning: CE3 T eacher s G uide - Module 1 Page 24

4 Folder 2: Ground Deformation (Mount St. Helens, Washington) Scientists use powerful instruments to monitor volcanic activity. Still, much of the work is done on the volcano. This can be very dangerous. Expand Folder 2: Ground Deformation and click on the radio button. Open the Mount St Helens, Washington placemark balloon. Read the information and record any observations you can. Then close the balloon. Observations What is ground deformation? What is a tiltometer? What does EDM stand for? How many readings were recorded on the EDM graph, including the original placement of the target? Over what time period and how many days were the targets tracked? Approximately how many meters did the target move over that time? What was the average speed at which the target moved? (cm/day) Does the slope of the line in the graph change very much? Did the target move at a relatively constant rate CE3 T eacher s G uide - Module 1 Page 25

5 during the time it was monitored? How wide is your classroom? (m) Interpretation Imagine that your classroom is on a volcano. Imagine that the ground below your classroom is being deformed at the same rate as it was at Mount St. Helens. How many days would it take to move your classroom to where the classroom next door now sits? Claim: Evidence: Reasoning: Folder 3: Hot Spots Scientists use special images to see things that they could not see otherwise. Step Complete 1. Expand Folder 3: Hot Spots and click on the radio button. Open the Chiliques, Chile placemark balloon. Read the information and record any observations you can. Then close the balloon. 2. Turn on the Infrared Image folder to see the infrared image of the Chilques volcano. Look at the legend. The hottest areas are white and coldest areas are black. Yellow, orange, and red are intermediate temperatures. Of these, yellow is the hottest and red is the coldest. Record this observation. 3. Notice that the colors in the image appear as squares. This is because the image is made CE3 T eacher s G uide - Module 1 Page 26

6 up of square pixels. Temperature is measured across each pixel. The block of color shows the average temperature of that area. Record this observation. 4. Examine the pattern of colors on the volcano and surrounding landscape. Look at the land surrounding the volcano, the dome of the volcano, and the top of the volcano. Record your observations. Observations What is remote sensing? What is visible light? What is infrared light? What is a pixel? In an infrared image, how are the colors ordered from hottest to coldest? Main colors of pixels surrounding the Chiliques volcano: Main color of pixels covering most of the volcano: Colors of pixels seen at the very top of the volcano: Monitoring conducted at some distance from the site. A small fraction of the radiation wavelength spectrum that we see as colors. Part of the radiation wavelength spectrum with wavelengths longer than visible light and which correspond to temperature. A square area over which information is averaged. White, yellow, orange, red, black Yellow, orange, red Black White, orange, red Interpretation Is magma near the surface at Chiliques? Claim: Evidence: CE3 T eacher s G uide - Module 1 Page 27

7 Reasoning: Folder 4: Gas Emissions Volcanologists can monitor the gases being given off by a volcano to help predict when it might erupt. This work can be quite dangerous. Expand Folder 4: Volcanic Gases and click on the radio button. Open the Mount Pinatubo, Philippines placemark balloon. Read the information and record any observations you can. Then close the balloon. Observations What is a fumerole? Most common types of volcanic gases: Are gases dissolved or undissolved under high pressure? What happens to gases in magma when the pressure drops? Are volcanic gases more or less dense than magma? Does the volume of the volcano s plumbing system increase or decrease as magma pushes outward through cracks and upward through the vent? CE3 T eacher s G uide - Module 1 Page 28

8 Does the pressure within the volcano s internal plumbing system increase or decrease as magma pushes outward through cracks and upward through the vent? Interpretation Would an increase in volcanic gas emissions indicate that magma below was moving? Claim: Evidence: Reasoning: Folder 5: Summary Expand Folder 5: Summary and click on the radio button. Open the Active Volcanoes placemark balloon. Read the information and watch the video. Then close the balloon and answer the questions below. Questions Are you surprised by how many active volcanoes there are? Why or why not? CE3 T eacher s G uide - Module 1 Page 29

9 Are the volcanoes randomly distributed across the globe? Describe any patterns you see. Going Further: USGS Hazards Program Explore the USGE Hazards Program website. Are there any eruption alerts right now? Are there any near where you live? Record your findings below and report them to your class. Findings Going Further: Gas Plumes Step Complete 1. Click on the Volcanic Gas Plumes folder radio button and expand the folder. Open the Soufrière Hills Volcano folder and the Soufrière Hills, Montserrat placemark. Read the information and record any information you can. 2. Click on the Gas Plume Tracking folder radio button and expand the folder. Cycle through the three overlays to see how the gas plume moved during the three days following the eruption. Note the change in color of the plume through time. Record your findings. 3. Use your ruler tool to determine how far the plume travelled in three days. Then calculate the average speed at which the plume travelled. Record your findings. 4. Use your observations to answer the interpretation question. CE3 T eacher s G uide - Module 1 Page 30

10 Observations Date of eruption: Method used to track the gas plume: Number of days gas plume was tracked: Altitude plume reached (km): Did the plume reach the stratosphere? (Refer to your notes from Laki in Investigation 1.) Direction plume travelled: Distance plume travelled (km): Average speed or rate at which plume travelled (km/day): Does the gas concentration increase or decrease over time? Interpretation Would you expect the gas plume from the Soufrière Hills volcano to become a hazard to human health? Claim: Evidence: Reasoning: CE3 T eacher s G uide - Module 1 Page 31