Skip to main content
Geosciences LibreTexts

8.7: Activity 8F- Volcanic Hazards

  • Page ID
    14819
  • Potential hazards associated with certain volcanic types can be identified using topographic maps or aerial photographs. In this exercise, use Google Earth and type in the locations into the search bar.

    1. Type Mount St. Helens, WA in the search bar in Google Earth and examine the crater and surrounding area, at an eye altitude of ~25,000 ft. What do you notice about the appearance of the crater?

    1. Using the measure tool, approximately how large is the gap in the crater wall?

      1. in meters:

      2. in feet:

    1. Find the highest elevation you can along the crater rim. Hint - the elevation will appear in the bottom right-hand corner. Hover your mouse anywhere on the screen to see the elevation.

      1. In feet, approximately:

    1. Find the lowest elevation you can around the volcano. Hint - the elevation will appear in the bottom right-hand corner. Hover your mouse anywhere on the screen to see the elevation.

      1. In feet, approximately:

    1. Ensure your view is in 2D (click on the 3D in the bottom right corner and it will switch back). Fly around the volcano. What is the overall shape?

    1. What type of volcano is Mt. St. Helens?

    1. Zoom out so that you can see the coastline and Mt. St. Helens. What type of plate boundary is forming Mt. St. Helens?

    1. How can you tell?

    1. Based on the information you collected above what likely caused the odd form in the crater:

    1. a lahar removed the north side of the volcano

    1. a pyroclastic eruption removed the north side of the volcano

    1. a lava dome grew so large that it is higher than the north side of the crater

    1. a glacier has eroded the north side of the crater

    1. Type Mount Rainier, WA in the search bar in Google Earth. Zoom out to an eye altitude of ~11 miles. Notice the spindly, arm-like features that surround the volcano. Which volcanic hazard do you think produced these features?

    1. Ash fall

    1. lahars

    1. Pyroclastic flows

    1. Lava flows

    1. How can you tell?

    1. Visit the Smithsonian Volcanism Program, a wonderful site, that puts over 10,000 years of volcanic eruptions at your fingertips. Search for volcanoes in the US from their database, scroll through the results to see the over 1100 volcanoes! Your instructor may have a specific volcano for you to look for, however if not, go ahead and select a volcano from a state other than California. Most of the volcanoes have a significant amount of information, however if you choose one without much data, select a new volcano. Familiarize yourself with the many tabs and facts regarding your volcano or volcanic system and answer the following,

      1. Where is the volcano located (provide a state or territory):

      2. What is the primary volcano type?

      3. What processes are producing magma here?

      4. Is there a date associated with the last eruption? If yes, indicate the date here:

      5. If available, what is the population density nearby?

    1. Visit the Smithsonian Volcanism Program, a wonderful site, that puts over 10,000 years of volcanic eruptions at your fingertips. Search for volcanoes in the US from their database, scroll through the results to see the over 1100 volcanoes! Your instructor may have a specific volcano for you to look for, however if not, go ahead and select a volcano from California. Most of the volcanoes have a significant amount of information, however if you select one without information, select a new volcano. Familiarize yourself with the many tabs and facts regarding your volcano or volcanic system and answer the following,

      1. What is the primary volcano type?

      2. What processes are producing magma here? Explain your answer. Hint - think about the overall tectonic location. It may be helpful to also locate your volcano in Google Earth to see where you are geographically.

      3. Is there a date associated with the last eruption? If yes, indicate the date here:

      4. Locate your volcano selection in Google Earth. What is the closest community (city, town, etc.)?

      5. How far is this community from the volcano?

      6. What is the population of this community?

    • Was this article helpful?