Fire and Ice: Identify and compare volcanic and glacial features on land and seafloor.
This lesson will familiarize students with the detailed bathymetric and satellite data that is collected and used by scientists to study the Earth. They will understand that the surface of the ocean floor is complex and varied. Scientists and students can use these types of data to study plate tectonics, ecosystems, natural hazards, climate change and Earth's history. Experience manipulating and examining data images will pique students' interest and inspire them to seek answers to their own questions.
- investigate volcanoes and glaciers in one of the youngest and most tectonically active regions of the United States, the Alaskan Peninsula.
- Explore and become familiar with geophysical data and its uses, specifically, multibeam sonar data, and satellite data and images.
- learn to use and interpret topographic and bathymetric maps to answer their own questions.
- become familiar with available technology used by scientists to image topography and bathymetry
- recognize surface and seafloor features formed by glaciers and volcanoes
- organize, present and discuss their observations in a classroom setting
Context for Use
Description and Teaching Materials
Alaskan Peninsula, Aleutian Island Tectonic Setting
Using a visualization of the seismic activity in Alaska, students will be introduced to the tectonic setting of this activity. Using iView3D the image can be manipulated and examined in 3 dimensions. The earthquake pattern clearly delineates a subduction zone, the Pacific Plate subducting beneath North America. Discussion about the tectonic setting and its causal relationship to the earthquake and volcanic activity in this area is a good starting point for the activity. Each earthquake location (hypocenter) is depicted as a point (~128,854 earthquakes), color-coded by time.
Sand Point Area, Alaskan Peninsula - Detail Area Bathymetry Map
Most people are familiar with mountains, valleys, plains and deserts. We have seen maps and photos of the planet we all share. Many of us are also familiar with processes that shape and change Earth's surface, erosion, weathering, glaciers, volcanoes, earthquakes, and moving plates. Erosion and weathering act over thousands and millions, even billions of years to carve river valleys like the Grand Canyon, and break down mountains into plains. Glaciers can move slowly across the landscape like giant bulldozers pulverizing and plucking rocks in their paths only to deposit them elsewhere as the glaciers recede and leave behind broad U-shaped valleys as evidence of their passage. When plates, slowly, over millions of years, collide, separate or slide past one another they may alter our landscape in spectacular and sometimes hazardous ways. Erupting, explosive volcanoes, deadly earthquakes that spawn tsunamis, and the beauty and energy of hotsprings and geysers are all examples of tectonic forces shaping our landscapes.
These forces of nature have direct effects on human lives. Scientists, engineers, and mathematicians have studied the Earth for centuries, and specialized technologies have been developed to extend our studies in new and expanded directions. One of those directions extends our knowledge of the Earth's systems and processes to the world's oceans. Oceans present a vast, largely unexplored frontier where many of the same processes that shape the familiar surfaces of the Earth are operating on the seafloor. Scientists and engineers have developed sonar systems that can map the ocean floor at a scale of a meter. These systems are used routinely along our country's coasts by NOAA scientists as they produce nautical charts for mariners. Bathymetric charts present accurate, measured descriptions and visual representations of the seafloor just as topographic maps give measured descriptions and visualizations of the terrain on land. Although bathymetry is not used as a navigational tool, the data can be used for many scientific endeavors and to extend our knowledge of the Earth and its systems.
The Alaskan Peninsula and the Aleutian Islands are a geologically complex area where earthquakes and active volcanoes are commonplace. The Aleutian archipelago is a fresh, sharp landscape of young volcanoes emerging from the ocean. This landscape has also been shaped and carved by glaciers. Volcanic cones have erupted into broad glacial valleys. Glaciers have eroded and shaped volcanic cones. Detailed mapping that extends unbroken from the highest mountains to the depths of the ocean is a powerful tool for studying, understanding and perhaps predicting Earth's dynamic processes. This land created by volcanic fire and glacial ice provides an outstanding study area to practice using bathymetry and topographic maps to examine and interpret evidence of the actions of glaciers and volcanoes.
Average Learning Time: 3 - 5 hours
- Bathymetric maps of the Sand Point area of Alaska
- Computers for student use
- Computer(s) with internet access
- Projector with computer access
- Review reference websites
- Install iView3D free imaging software on at least one computer
- Download the Seismic Activity in Alaska scene file from the library of the SIO Visualization Center at Scripps Institution of Oceanography. This is a big file, so it takes time to download. Open the file in iView3D and practice moving in 3 dimensions through the scene file and using the zoom features. Be sure you are able to identify the tectonic plates by examining the subduction zone and the pattern of earthquakes. Try locating the detail map area around Pavlof Volcano. Note that resolution of individual volcanoes is difficult at this scale.
- Download Virtual Ocean
- Use Virtual Ocean to locate Sand Point, AK, near the end of the Alaskan Peninsula. From the Global Multi-resolution Topography Data Portal , choose Virtual Ocean from the sidebar list. Download the Virtual Ocean application. Choose Mercator projection. When the world map appears choose "available data" from the toolbar. In order choose: Select data from menu; layers; contributed regional bathymetric grids; U.S. continental margin; Alaska; Sand Point Alaska. The map will appear and using the toolbar, you can manipulate it and save maps in several formats. It might also be useful to match the Google map area to the bathymetric map area.
- Print and laminate one copy of the bathymetric map for each group of 3 to 4 students.
Lesson 1 - OpeningIt is important to access the students' prior knowledge with a quick review of glaciers and the Theory of Plate Tectonics. Ask the students what a glacier is and how it moves. Where could they see glaciers in the United States? When did the last ice age end (about 10,000 years ago)? Review the tectonic setting of the Alaskan Peninsula by looking at the 3D visualization, Seismic Activity in Alaska. Have the students write down questions. Students should realize that earthquakes and volcanoes, possible hazards to humans, are closely associated with the Pacific Ring of Fire and subduction zones. Students should be impressed with the data and technology used to produce the 3D visualization. Zoom in on the Pavlof Volcano, about midway along the Aleutian Arc, and ask the students if they can see evidence of volcanic and glacial activity. The resolution is not quite good enough to see individual features. Ask students how they would find detailed maps of glaciers and volcanoes? At this point students should be interested in finding out more about this area of the U.S.
Gather questions from the class and compile a list. It would be wise to restrict questions to glaciers and volcanoes even though there are obviously earthquakes associated with subduction zones. The purpose of this lab is to acquaint students with technology and tools available for them to use to answer their own questions. Students will use one of these technological products, multibeam sonar data from Sand Point, Alaska, to conduct research and answer questions about glaciers and volcanoes.
Explain to the students that they will work in small groups, using computers and maps to find information and look more closely at volcanic and glacial features. They will be using evidence from topographic and bathymetric maps to answer questions for a lab report. Each group will choose at least one additional question from the list to answer by conducting research at the scientific websites listed below and/or by investigating the topographic and bathymetric maps.
Lesson 2 - Data AcquisitionStudents should be divided into groups of 3 to 4 to conduct the inquiry activity.
Small groups should work together using the maps and computers to answer the questions on the lab and the question they have chosen from the list (developed by the class during lesson 1).
This can most easily be accomplished with two computers per group. One should display the Virtual Ocean map showing the topography and bathymetry of the area. The other computer can be used to access the websites listed under "Resources" to find the answer to the group's question about glaciers or volcanoes.
Note: I do not allow my students to access websites other than those that I have provided unless I am directly supervising them, and we are working on the question together. Sometimes I do some additional research outside of class and then add websites to a student's list when appropriate.
Often at the beginning of an inquiry activity of this nature there is some confusion as the students settle into their roles in the group and get the idea of the work required. I typically visit each group and get them started gathering data from the maps. I also have a lab report template that my students use when gathering data from websites. I usually embed the hyperlinks in that lab report, so the students have easy access to the links and are not tempted to look elsewhere for information (see attachment #2).
Fire and Ice Lab: Inquiry into surface features created by glaciers and volcanoes.
(See References and Resource below.)
Lesson 3: Lab reportEvaluation and Assessment: Lesson 4 - The Map should be projected, and each group should present the answer to their question and the results of their lab report research to the class. This gives the teacher a chance to assess the students' work, correct any misconceptions through class discussion. This type of evaluation and assessment also gives the students a chance to practice presentation and discussion skills. Collect the lab reports from each group after each presentation. The lab reports should be graded. Background information for students and lab report template (Microsoft Word 2007 (.docx) 15kB Apr16 09)
Teaching Notes and Tips
References and Resources
Photographs and descriptions of Alaskan glaciers
NOAA's on line nautical chart viewer map showing the area of study
Information about glaciers and how they move along with spectacular photos
Photos of the Pavlof Volcano area and descriptions of how hydrographers collect data to compile bathymetric maps
Alaskan Volcano Observatory
Information about making 3D images to display data, SIO Visualization Center
Marine Geoscience Data System (MGDS): Global Multi-resolution Topography(GMRT) - This portal can be used in many ways to conduct research and answer questions about the seafloor.
Bathymetry Wiki Page provides a description of bathymetry
Geologic Map of Alaska