2006 Submarine Ring of Fire It’s Going to Blow Up! (adapted from the 2005 New Zealand American Submarine Ring of Fire Expedition) FOCUS TEACHING TIME Volcanism on the Pacific Ring of Fire One or two 45-minute class periods, plus time for student research GRADE LEVEL 7-8 (Earth Science) SEATING ARRANGEMENT Classroom style if students are working individu- FOCUS QUESTION ally, or groups of two to four students What are major characteristics of volcanoes on the Pacific Ring of Fire? MAXIMUM NUMBER OF STUDENTS 30 LEARNING OBJECTIVES Students will be able to describe the processes KEY WORDS that produce the “Submarine Ring of Fire.” Volcano Caldera Students will be able to explain the factors that Cascade Mountains contribute to explosive volcanic eruptions. Ring of Fire Asthenosphere Students will be able to identify at least three ben- Lithosphere efits that humans derive from volcanism. Magma Fault Students will be able to describe the primary risks Transform boundary posed by volcanic activity in the United States, Convergent boundary and will be able to identify the volcano within the Divergent boundary continental U.S. that is considered most danger- Subduction ous. Tectonic plate Mariana Arc MATERIALS Copies of “Ring of Fire Volcanism Worksheet,” BACKGROUND INFORMATION one copy for each student or student group The Submarine Ring of Fire is an arc of active vol- canoes that partially encircles the Pacific Ocean AUDIO/VISUAL MATERIALS Basin and results from the motion of large pieces (Optional) Equipment for viewing video clips of the Earth’s crust known as tectonic plates. from the Ocean Explorer Web site These plates are portions of the Earth’s outer crust (the lithosphere) about 5 km thick, as well as the upper 60 - 75 km of the underlying mantle. The 1 2006 Submarine Ring of Fire – Grades 7-8 (Earth Science) Focus: Volcanism on the Pacific Ring of Fire oceanexplorer.noaa.gov plates move on a hot flowing mantle layer called In 2003, the Ocean Exploration Ring of Fire the asthenosphere, which is several hundred expedition surveyed more than 50 volcanoes kilometers thick. Heat within the asthenosphere along the Mariana Arc, and discovered that ten creates convection currents (similar to the currents of these had active hydrothermal systems (visit that can be seen if food coloring is added to a http://oceanexplorer.noaa.gov/explorations/03fire/welcome. heated container of water) that cause the tectonic html for more information on these discoveries). plates to move several centimeters per year rela- The 2004 Submarine Ring of Fire Expedition tive to each other. focussed specifically on hydrothermal systems of the Mariana Arc volcanoes, and found that these If tectonic plates are moving apart their junction systems are very different from those found along is called a divergent plate boundary; if they slide mid-ocean ridges (visit http://oceanexplorer.noaa.gov/ horizontally past each other they form a transform explorations/04fire/welcome.html for more information). plate boundary; and if they collide more or less The 2006 Submarine Ring of Fire Expedition is head-on they form a convergent plate boundary. focussed on interdisciplinary investigations of the The Pacific Ocean Basin lies on top of the Pacific hydrothermal and volcanic processes on the sub- Plate. To the east, new crust is formed by magma marine volcanoes of the Mariana Arc. rising from deep within the Earth and erupting at divergent plate boundaries between the Pacific On April 1, 2004, scientists exploring the NW Plate and the North American and South American Rota #1 volcano reported the first-ever direct Plates. These eruptions form submarine mountain observations of a submarine volcanic eruption. ranges called oceanic spreading ridges. While the In this lesson, students will investigate some process is volcanic, volcanoes and earthquakes characteristics of volcanoes associated with the along oceanic spreading ridges are not as violent Submarine Ring of Fire, including volcanoes pres- as they are at convergent plate boundaries. ent within the continental United States. To the west, the Pacific Plate converges against LEARNING PROCEDURE the Philippine Plate. The Pacific Plate is forced 1. To prepare for this lesson, read beneath the Philippine Plate, creating the • Introductory essays for the 2006 Submarine Marianas Trench (which includes the Challenger Ring of Fire Expedition at http://oceanexplorer.noaa. Deep, the deepest known area of the Earth’s gov/explorations/06fire/welcome.html; and ocean). As the sinking plate moves deeper into • Submarine Ring of Fire 2004 daily logs for the mantle, fluids are released from the rock caus- April 1 and April 4 (http://oceanexplorer.noaa.gov/ ing the overlying mantle to partially melt. The explorations/04fire/logs/april01/april01.html; and http:// new magma (molten rock) rises and may erupt oceanexplorer.noaa.gov/explorations/04fire/logs/april04/ violently to form volcanoes, often forming arcs april04.html). of islands along the convergent boundary. The Mariana Islands are the result of this volcanic You may also want to visit the US Geological activity, which frequently causes earthquakes as Survey’s Cascades Volcano Observatory Web well. The movement of the Pacific Ocean tectonic site (http://vulcan.wr.usgs.gov/) to become familiar plate has been likened to a huge conveyor belt with the resources available. on which new crust is formed at the oceanic spreading ridges off the western coasts of North 2. Briefly review the concepts of plate tectonics and South America, and older crust is recycled to and continental drift and how they are related the lower mantle at the convergent plate boundar- to underwater volcanic activity. You may want ies of the western Pacific. to use resources from NOAA’s hydrothermal 2 2006 Submarine Ring of Fire – Grades 7-8 (Earth Science) oceanexplorer.noaa.gov Focus: Volcanism on the Pacific Ring of Fire vent Web site (http://www.pmel.noaa.gov/vents/home. (5) These volcanoes were selected for explora- html) and possibly the video clips linked to the tion because they show evidence of having Submarine Ring of Fire 2004 daily log for active hydrothermal systems. April 1 to supplement this discussion. Introduce the Submarine Ring of Fire, and describe the (6) Macauley, Brothers, Monowai, W, and processes that produce the island arcs. Tell Healy students that the 2006 Submarine Ring of Fire Expedition is focussed on more detailed investi- (7) Mafic lavas have high concentrations of gations of Mariana Arc volcanoes. magnesium and iron. 3. Tell students that their assignment is to familiar- (8) The Cascade mountains in the western ize themselves with some basic concepts of United States are part of the Pacific Ring of volcanology and to investigate a portion of the Fire. Ring of Fire that is present within the continental United States. Provide each student or student (9) More than 80 percent of the Earth’s surface group with a copy of “Ring of Fire Volcanism is of volcanic origin. Worksheet,” and direct students to research the answers to questions on the worksheet. You (10) Volcanic ash increases soil fertility by add- may also to provide formulas for the volume of ing nutrients. Groundwater heated by hot a cone and volume of a sphere, or may let stu- magma can be used for geothermal energy. dents find these on their own. Volcanic processes concentrate valuable min- erals into deposits that include most of the 4. Lead a discussion of students’ answers to work- metallic minerals mined in the world. sheet questions. The correct answers are: (11) The May 18, 1980 eruption of Mount St. (1) Felsic magmas and the formation of big Helens, Washington was the most destructive calderas are associated with the most violent volcanic eruption in the history of the United volcanic eruptions. States. (2) Magmas with high silica content are dan- (12) Mauna Loa, Hawaii is the largest active gerous because silica molecules make volcano in the world. magmas very viscous, and the high viscosity traps gasses, producing pressures that result (13) Indonesia, Japan and the United States in explosive eruptions. have the most historically active volcanoes. (3) A caldera is a huge depression at the top (14) Eruptions in the Cascades occur at an of a volcano formed by explosive eruptions average rate of 1-2 per century. that remove large volumes of magma from beneath a volcano, causing the ground to (15) Mount Garibaldi in British Columbia, collapse into the emptied space. Canada erupted through a glacier. (4) The volcanos Macauley, Brothers, Monowai, (16) Mount Rainier, Washington is potentially W, Healy, Rumble-III, Rumble-V, Tangaroa, the most dangerous volcano in the Cascades and Clark are scheduled for exploration by because of its great height, frequent earth- the Submarine Ring of Fire 2006 expedition. quakes, active hydrothermal system, and 3 2006 Submarine Ring of Fire – Grades 7-8 (Earth Science) Focus: Volcanism on the Pacific Ring of Fire oceanexplorer.noaa.gov extensive glacier mantle, although Mt. debris which gives them the internal strength Ranier has not produced a significant erup- to transport huge boulders, buildings and tion in the past 500 years. bridges. Lahars exert extremely high impact forces against objects in their paths. (17) The greatest hazard presented by Mt. Ranier is a mixture of mud and rock debris To solve the “Geometry Challenge” students known as a “debris flow,” which looks and need to find the volume of material that would behaves like flowing concrete. Debris flows have been removed from the original West Rota are unpredictable and may occur indepen- volcano to produce the present form. This mate- dently of a volcanic eruption, and could rial can be represented as a cone resting on cover the distance between Mount Rainier one half of a sphere. The base of the cone is and the Puget Sound lowland in as little as 10 km across, and its height is approximately 30 minutes.