Skip to Content

Volcanoes and Their Activity

Course Number: G 208
Transcript Title: Volcanoes and Their Activity
Created: September 1, 2012
Updated: August 4, 2015
Total Credits: 3
Lecture Hours: 30
Lecture / Lab Hours: 0
Lab Hours: 0
Satisfies Cultural Literacy requirement: No
Satisfies General Education requirement: Yes
Grading options: A-F (default), P-NP, audit
Repeats available for credit: 0
Approved delivery mode:


MTH 65 or equivalent placement test scores

Prerequisite / Concurrent

WR 121

Course Description

Covers the origin, activity, products, classification and hazards of volcanoes. Prerequisite: MTH 65 or equivalent placement test scores. Prerequisite/concurrent: WR 121. Audit available.

Intended Outcomes

A student who successfully completes this course should be able to:

  1. Use an understanding of rock and mineral characterization and classification to infer the igneous processes which formed individual rock and mineral specimens.
  2. Analyze the development, scope, and limitations of plate tectonics and utilize plate tectonics to explain the Earth’s volcanic activity, and the relationship of this activity to climate change, agriculture, and formation of economic deposits.
  3. Access volcano science information from a variety of sources, evaluate the quality of this information, and compare this information with current models of volcanic processes identifying areas of congruence and discrepancy.
  4. Make field and laboratory based observations and measurements of volcanic rocks and minerals and/or volcanic landforms, use scientific reasoning to interpret these observations and measurements, and compare the results with current models of volcanic processes identifying areas of congruence and discrepancy.
  5. Use scientifically valid modes of inquiry, individually and collaboratively, to critically evaluate the hazards and risks posed by volcanoes both to themselves and society as a whole, evaluate the efficacy of possible ethically robust responses to these risks, and effectively communicate the results of this analysis to their peers.
  6. Assess the contributions of volcanology to our evolving understanding of global change and sustainability while placing the development of volcanology in its historical and cultural context.

Alignment with Institutional Core Learning Outcomes

1. Communicate effectively using appropriate reading, writing, listening, and speaking skills. (Communication)
2. Creatively solve problems by using relevant methods of research, personal reflection, reasoning, and evaluation of information. (Critical thinking and Problem-Solving)
3. Apply the knowledge, skills and abilities to enter and succeed in a defined profession or advanced academic program. (Professional Competence)
4. Appreciate cultural diversity and constructively address issues that arise out of cultural differences in the workplace and community. (Cultural Awareness)
5. Recognize the consequences of human activity upon our social and natural world. (Community and Environmental Responsibility)

Outcome Assessment Strategies

At the beginning of the course, the instructor will detail the methods used to evaluate student progress and the criteria for assigning a course grade. The methods may include one or more of the following tools: examinations, quizzes, homework assignments, research papers, small group problem solving of questions arising from application of course concepts and concerns to actual experience, oral presentations, or maintenance of a personal work journal.

Course Activities and Design

The material in this course will be presented in a lecture/discussion format. Other educationally sound methods may be employed such as guest lectures, field trips, research papers, and small group work.

Course Content (Themes, Concepts, Issues and Skills)

  1. Describe the relationship of volcanoes to plate boundaries.
  2. Classify the types of rocks created by volcanic processes.
  3. Contrast pyroclastic and effusive eruption styles.
  4. Examine the effect of silica content on eruption style.
  5. Discuss a number of historical volcanic eruptions and determine the major cause of human destruction for each case.
  6. Explore the methods used to forecast volcanic eruptions.
  7. Classify the features that occur in volcanic landscapes.
  8. Define the different kinds of plutons.
  9. Discuss the hazards associated with the Cascade volcanoes.
  10. Define the following terms: shield volcano, composite volcano, cinder cone, lahar, pyroclastic flow, pahoehoe, aa.
  11. Discuss the effects of volcanic eruptions on climate.

Topics to be covered include:

  1. Global Volcanic Activity
    1. Number and geographic distribution of active volcanoes
    2. Major historic volcanic eruptions and their impact on society (e.g. Tambora, Krakatau, Vesuvius, Mount Saint Helens)
    3. Active vs. dormant vs. extinct volcanoes
  2. Volcanic Eruptions
    1. Different styles of volcanic eruptions: effusive vs. explosive, Icelandic, Hawaiian, Strombolian, Vulcanian, Plinian and caldera type; lava flows, lava domes, eruption columns, pyroclastic flows, lahars, lateral blasts, landslides
    2. Phreatic eruptions vs. magmatic eruptions; submarine eruptions; sub glacial eruptions
    3. Sizes of volcanic eruption, VEI
  3. Volcanic Features
    1. Volcanic systems: volcanoes, vents, fissures and magma chambers
    2. Types of volcanoes: cinder cones, domes, shield volcanoes, stratovolcanoes, lava plateaus, calderas, maars, tuff rings
    3. Intrusive features; stocks, necks, cyptodomes, sills, dikes, plutons, batholiths
    4. Volcanic features in the Portland area, Cascades, Columbia River Basin and eastern Oregon
  4. Products of Volcanic Eruptions
    1. Chemistry of magmas: major elements and volatiles; physical properties of magmas: freezing temperature and viscosity; relationships between magma chemistry and physical properties
    2. Relationship between cooling rate and igneous rock textures
    3. Description and classification of igneous extrusive rocks: rhyolite, dacite, andesite, basalt, scoria, pumice, obsidian, vesicles, porphyritic texture
    4. Description and classification of igneous intrusive rocks: granite, granodiorite, diorite, gabbro, peridotite
    5. Lava flow features: pahoehoe vs. aa, lava tubes, cooling columns, tree casts, pillows, palagonite breccias etc.; identifying lava flow tops and bottoms in the field
    6. Pyroclastic products: ash, lapilli, cinders, bombs, tuffs, welded tuffs, flow tuffs
    7. Gases: types, quantity; sources: meteoric vs. magmatic
    8. Lahars: dynamics, distance and speed of flow, temperature; causes
    9. Pyroclastic flows: dynamics, distance and speed of flow, temperature, deposits, causes
    10. Lateral blasts: dynamics, distance and speed of flow, temperature, deposits, causes
    11. Landslides: dynamics, distance and speed of flow, temperature, deposits, causes
  5. Causes of Volcanic Eruptions
    1. Migration of magmas to shallow magma chambers, cooling and differentiation of magma chambers, differences between mafic and felsic magma chambers
    2. Role of exsolved gasses in driving volcanic eruptions
  6. Plate Tectonics and Volcanism
    1. Basic idea of plate tectonics, evidence for plate motion, difference between continental and oceanic crust, internal structure of the earth, heat loss and plate tectonics
    2. Creation of oceanic crust at mid ocean ridges, volcanism and hydrothermal activity at mid ocean ridges, cause of melting at mid ocean ridges, types of magmas produced
    3. Destruction of oceanic crust at subduction zones, volcanism associated with subduction zones, cause of melting at subduction zones, types of magmas produced
    4. Hot spots and associated volcanism in oceanic and continental settings, cause of melting, types of magma produced,
    5. Relationships between tectonic setting, cause of melting, magma type produced and eruption style
  7. Living with Volcanoes
    1. Volcanic hazards: lava flows, volcanic gases, eruption columns, ash falls, pyroclastic flows, lahars, landslides, lateral blasts
    2. Volcanic hazard mapping: use of volcanic deposits to determine past eruptive behavior and frequency of volcanoes, identifying hazard zones
    3. Preparing for volcanic eruptions; personal disaster kits, volcano monitoring, evacuation plans, effective communication of scientific information, education of public
    4. Predicting volcanic eruptions: monitoring precursors (earthquakes, deformation, gas emissions): possible triggers
    5. Case studies of volcanic eruptions including successful (e.g. Mt. Pinatubo) and unsuccessful (e.g. Nevado del Ruiz) societal responses with an emphasis on Cascade volcanoes
    6. Resources associated with volcanoes: geothermal energy, hot springs, tourism, volcanic soils, mineral deposits, diamonds
  8. Global Impacts of Volcanism
    1. Climate changes associated with historic eruptions, causes of these changes
    2. Flood basalt volcanism: Columbia River Basalts and other large igneous provinces
    3. Possible links between volcanism and mass extinctions
    4. Volcanic degassing as a possible source of the atmosphere and ocean

Department Notes

Volcanoes and Their Activity (G208) is a one-term introductory course in volcanology, which is a branch of the science of geology. The student will develop an understanding of the types, origin, activity, products, and hazards of volcanoes. This course can be used to partly fulfill graduation requirements for the Associate Degree, and has been approved for block transfer. The text and materials have been chosen by the faculty and the emphasis of the course will be the viewpoint of the author(s). This includes the geologic time scale and the evolution of the Earth.

Columbia Gorge Community College Science Department stands by the following statement about regarding science instruction:

Science is a fundamentally nondogmatic and self-correcting investigatory process. Theories (such as biological evolution and geologic time scale) are developed through scientific investigation are not decided in advance. As such, scientific theories can be and often are modified and revised through observation and experimentation. “Creation science", “Intelligent design” or similar beliefs are not considered legitimate science, but a form of religious advocacy. This position is established by legal precedence (Webster v. New Lenox School District #122, 917 F. 2d 1004).

The Science Department at Columbia Gorge Community College therefore stands with organizations such as the National Association of Biology Teachers in opposing the inclusion of pseudo-sciences in our science curricula except to reference and/or clarify its invalidity.

Students are expected to be able to read and comprehend college-level science texts and perform basic mathematical operations in order to successfully complete this course.

Lab B Notes: The lab for this course has been approved as "Lab B". This means that Faculty effort in preparation and evaluation generally occurs outside of scheduled class hours. Class format is a combination of Faculty lectures and demonstrations, guided student interactions and supervised student application of lectures. Students produce written work such as lab notebooks, reports, and responses in writing to assigned questions, and the Instructor is expected to comment on and grade this written work outside of schedule class hours. This evaluation will take place on a regular basis throughout the term.