Unit 3: Yellowstone is active, but is it erupting?
An eruption at Yellowstone could have devastating effects on large areas of the US and Canada, but what is the likelihood of such an eruption occurring? This unit has students explore seismic data for the last several decades and calculate mean recurrence intervals of seismic swarm events. Additional geodetic data (GPS, InSAR) are used to investigate whether or not seismic swarm events reflect volcanic activity. Finally, students will explain the source and causes of earthquake swarms in the context of responding to non-scientists' concerns that swarms indicate an impending eruption.
Unit 3 Learning Outcomes
- Distinguish earthquake swarms from background (non-active) data
- Calculate mean recurrence intervals (MRI) for earthquake swarms
- Determine that magmatic activity would be supported by consistent signals from multiple data types.
- Communicate the probability of risk of volcanic eruption based on geodetic data to a non-expert.
Context for Use
This unit is designed for an introductory level non-majors geoscience course, but can be adapted to low- to mid-level Volcanology, Geologic Hazards and other courses. The unit can be completed in a 50 -75 minute class period if introductory materials are completed by students as pre-work (as noted in Teaching Materials). It may be helpful but not necessary for students to be familiar with different volcano types, tectonic environments and magma sources, but a brief eruptive history of Yellowstone is introduced in the instructor presentation for this unit. Students should also be able to read and interpret seismic, GPS and InSAR data in the context of monitoring volcanoes, which is introduced in Units 1 and 2, but introductory materials are also provided in the References and Resources section below.
Description and Teaching Materials
Note this work can be completed at the beginning of in-class work for class periods of 75 minutes or more or can be assigned to students to complete prior to class (e.g. for class periods of 50 min).
- Student Pre-Reading with questions embedded (Microsoft Word 2007 (.docx) 1.7MB Jul2 19)
- Student Worksheet for digital submission (Microsoft Word 2007 (.docx) 254kB Jul2 19)
Instructor's note: Pre-work introduces students to Mean Recurrence Intervals (MRI) for volcanic eruptions, so that students can calculate MRIs for earthquake swarms in the in-class activities. Pre-work guides students through calculating MRI for eruptions in the Lassen region and at Mount Baker. Instructors can change the MRI table using data from the Smithsonian Institution's Global Volcanism Network where one can search for a specific volcano and the "Eruptive History" tab to compile data for MRI calculations.
Optional pre-work: Students who have not completed unit 2 may benefit from Pre-class readings for unit 2, about the use of Seismic, GPS, Tilt and InSAR data in volcano monitoring.
Part 1. Exploration of Yellowstone Seismic Data and Calculating a Mean Recurrence Interval (25 minutes)
Materials: Instructor Presentation (PowerPoint 2007 (.pptx) 12.8MB Jul2 19)
- Student worksheet (Microsoft Word 2007 (.docx) 2MB Jul2 19).
- Student Data Part 1 (Microsoft Word 2007 (.docx) 294kB May31 19)
- Student Data Part 2 (PowerPoint 2007 (.pptx) 6.1MB May31 19)
Note: Key to Student Worksheet is below in Assessment section.
- Introductory material that builds on information in pre-class work is included in the Instructor Presentation including a discussion that follows up the work on seismic swarms. Students will come to a working definition for class (as a class or in small groups)
- Seismic Data by Decade (10 minutes): Each student group (total of 4 groups, or for larger enrollment courses, multiples of 4 groups) is provided with a different decade of seismic data from Yellowstone (in Student Data part 1 file). Students are asked to answer the following questions in their groups (questions are in the Instructor Presentation and Student Worksheet)
- What is your working definition of a seismic swarm?
- When did the seismic swarm(s) occur?
- What was the duration of the swarm(s)?
- What was the size of the swarm(s) (how large of an increase relative to the overall decadal trend)?
- Calculate the MRI for the full data set (recall students calculated MRI in pre-work so should know how to do this - it might help to have students calculate the MRI for their own decade first if it helps with practice)
- Report Out (5 minutes) Instructor projects slide with Table 1 onto which students can fill in responses for their given data (instructor can project table onto a white board that students fill in, or students can type their answers into the table, or instructor can type students' responses to fill in the table). Students should make this table in their notes or instructor can provide the Student Worksheet file to them.
- Hypothesis Discussion (#6 in Student Worksheet; 10 minutes) Students work in groups to generate questions about the data. Possible guiding questions in Instructor Presentation
- What questions are emerging from the data?
- What are some possible explanations?
- What other data would you want in order to be able to help address these multiple working hypotheses?
(Note: Students should record their responses in the Student Worksheet)
Part 2. Assessing the State of Yellowstone (25 minutes)
- Examine multiple data types (10 minutes): Instructor provides student groups with GPS and InSAR data (Student data part 2) and assigns each group one of four GPS stations to complete the following tasks (also listed in Instructor Presentation and Student Worksheet). Responses to questions 8-11 can be recorded in the appropriate GPS station row on Table 2. It may help to copy and paste the seismic dates from Part 1 into the table 2 on the powerpoint slide:
7. Record the Seismic (from previous section) and GPS (of assigned station). Note there is a slide that shows how to interpret time series GPS data that instructors may use to help students.
8. Fill in the InSAR data. Note there is a slide with a reminder of what the fringe sequence indicates about inflation vs. deflation.
9. Compare and contrast all data types and discuss the geologic events recorded by the combination of all data types through a lens of internally consistent among data types or not. It may help to make it as basic as yes there is a correlation, no there is not a correlation and it is uncertain if there is a correlation if time is an issue, but recognize that this may diminish the nuances of the class discussion of data.
10. Students report out their interpretations.
11. Discuss reasons for non-magmatic seismic, GPS and InSAR movement.
(Note: students should record information in Table 2 and be ready to discuss. Good responses are in the Student Worksheet Key)
- Report out (5-10 minutes): Instructor uses the Instructor Presentation to guide student groups in reporting their answers to questions 6-8 to the class, including a summary of all data types and their interpretation of what combined data mean for magmatic activity at Yellowstone during this time.
- Class discussion (5 -10 minutes): Instructor uses in the Instructor Presentation to lead a class discussion in responses to question 8-11 (interpretations plus examination of internal consistency of data as described in the Instructor Presentation and Student Worksheet), leading to the idea that GPS and InSAR data do not indicate volcano activity during the time of seismic swarms and that earthquakes may represent activity that is not associated with an eruption (e.g. tectonic earthquakes and hydrothermal activity). Possible responses are provided in the Student Worksheet Key
Teaching Notes and Tips
Mechanics of the Activity
- The Instructor Presentation slides are designed to guide the instructor/students through the activity. Notes in slides provide example responses. The last slide of the Instructor Presentation file previews the Summative Assessment Option 1 activity (see Assessment section below), and some instructors may opt to not use that activity (so can delete the slide), but the activity could also be used as an in-class discussion, so is included here.
- Especially for large classes, it might be most efficient to have students remain in the same group for Part 1 and Part 2 of the activity.
- If one chooses to update the seismic information, the details of how these data were accessed and compiled are available in seismic data download instructions (Text File 786bytes Aug9 18).
- The graphs in the student data files are from these spreadsheets. Instructors who wish to add to or adjust the graphs can work from them:
- This activity is designed to facilitate student-student interactions which foster student learning by requiring them to negotiate the content among themselves. This active learning approach is based on what research indicates is most effective for student learning, however some students can be resistant to this approach for a number of reasons including:
- A perception that they're not learning from experts: it may help to address this by indicating to students the reason for your approach and some of the research in how this ultimately results in greater success by the students and supports skill development sought by employers (see an overview and and resources about engaged pedagogies).
- They lack confidence in their own capabilities: this unit has opportunities for students to build on each others work and learn by correcting any mistakes, so that students can take risks in failure and still benefit and learn. In addition, the lesson is designed to help them build their confidence or self-efficacy as they learn more.
- They are introverted and do not like to interact with others: this is a tricky one, as students may always default to the silent role. Assigning roles may help with asking students to take on different assigned roles, and there are also aspects of this lesson that can help introverts "recenter" by having more silent reflection time.
- When calling on individuals for responses to whole-class discussions, it can help to ask only when there are more than one correct answer and/or provide students time to talk to their neighbors through Think-Pair-Share before sharing out. These can help to alleviate the concerns of being "wrong." In addition, using clickers in large classes, raising hands, or thumbs up/thumbs down options can easily gauge where students are for alert levels and then lead to sharing in smaller groups.
Very Small- and Large- Enrollment Courses:
Group Activities are often most effective with groups of 3-5 students.
- Courses with very small enrollment (e.g. less than 15 students) can divide topics among a smaller number of groups (e.g. two groups that look at two data decades of seismic data each, during Parts 1 and 2). This will likely also use more class time. Alternatively, instructors of small enrollment courses can provide results/input for some decades so students only have to interpret one decade of data but can use all decades in their analysis during part 2.
- Instructors of courses with more than 15-20 students can organize multiple sets of jigsaw groups so that there are several groups interpret each decade. During report-outs, all groups can contribute (Phase 5).
- All-class report- outs can be modified to have students respond using clickers or even a free online program such as Poll Everywhere in which students use their cell phones.
- Distributing handouts can be time-consuming in very large enrollment courses, but can be facilitated by preparing sets of handouts that can be retrieved by a single group member. It may save time to have stacks of handouts around the room. In some cases, geology majors or geology/science club members can be recruited to help distribute handouts in class.
- Part 1: Instructors can collect students responses to the student worksheet from Table 1, or can gauge student understanding from verbal responses to discussion in Part 1 about seismic swarms selected and MRI's calculated.
- Part 2: Instructors can collect students responses to Questions in Table 2, or can gauge student understanding from verbal responses to discussion about the correlation of the data types and report outs from the GPS and InSAR analysis.
The student exercise can be the primary summative assessment for the unit.
[all unit outcomes addressed]
OPTIONAL Additional Summative Assessment:
Option 1: Exam questions
- Unit 3 sample exam questions (Microsoft Word 2007 (.docx) 327kB Dec22 18)
[Learning Outcomes 1 & 2 addressed]
Option 2: Students will construct a written response to a "conspiracy theorist" who expresses concern that there is an impending eruption at Yellowstone.
- USGS scientists at the Yellowstone Volcano Observatory regularly receive emails from individuals who believe that the observatory staff is hiding information about an impending eruption (example Yellowstone conspiracy letter (Microsoft Word 2007 (.docx) 314kB Oct3 18)).
- Use data from the in-class activity PLUS the current data (available at the map of monitoring instruments at Yellowstone) to support the letter you write.
- Keep in mind that sometime you need to appeal to more than just facts to help convince a person (for example, the Global Weirding video from Katherine Hayhoe describing the social science behind Why people don't believe in climate science and how to move beyond just facts to create a more convincing argument.
- Grading criteria for student-written response letters: Conspiracy response letter rubric (Microsoft Word 2007 (.docx) 348kB Jan14 19)
[Learning Outcome 3 & 4 addressed]
References and Resources
Introductory materials on using GPS, Seismic and InSAR data are included in pre-readings for Unit 2, which will be useful for students who did not participate in Unit 2 (or are otherwise unfamiliar with GPS, seismic and InSAR data)
Background information about reading and interpreting volcano monitoring data for students to learn the basics of data associated with volcano monitoring, so they can interpret data in this unit:
- Map of Yellowstone monitoring instruments
- UNAVCO's Borehole Strainmeter (seismic) data.
- USGS graphs of Yellowstone earthquake swarms in 1985, 1995, 2004 and graphs of annual earthquakes at Yellowstone.
- InSAR USGS Professional Paper 1788 is available online, which includes interferograms for Yellowstone
- LiDAR data can be accessed (although it is not data used in this unit)
Additional Resources for Students and Instructors:
- Geodesy is the measurement and monitoring of the size and shape of Earth included within a three-dimensional, time varying space), more info at What is Geodesy?
For more on interpreting geodetic data, see:
- GPS: see a tutorial on using GPS data
- Seismic: Using seismic data (earthquakes) to monitor volcanoes
- Tilt: USGS has more information on using tilt data to monitor volcanoes
- InSAR: The GETSI module Imaging Active Tectonics with InSAR and Lidar has a presentation with more information on how InSAR works. The application in that case is earthquake deformation but the concept is the same for sensing volcanic deformation.
- Presentation on the background theory of InSAR (PowerPoint 2007 (.pptx) 11.7MB May4 18)
- LiDAR: See a NASA review of Mount St Helens Lidar
Additional Resources for Instructors:
- The GETSI module Imaging Active Tectonics with InSAR and Lidar has a presentation with more information on how InSAR works. The application in that case is earthquake deformation but the concept is the same for sensing volcanic deformation.
- Presentation on the background theory of InSAR (PowerPoint 2007 (.pptx) 11.7MB May4 18)
More information about Yellowstone in accessible formats include:
- Tracking Changes in Yellowstone's Restless Volcanic System from the USGS
- Steam Explosions, Earthquakes and Volcanic Eruptions - What's in Yellowstone's Future?
- USGS webpage about Supervolcanoes
- USGS has maps showing monitoring at Yellowstone
- Dr. Jake Lowenstern (YVO Scientist in Charge in 2009) describes a 2008-2009 seismic swarm at Yellowstone in a podcast
- A recent Nature Geoscience article caused some (unfounded) speculation that Yellowstone may erupt soon. This is an example of scientific data being taken out of context, but may be useful, especially in more advanced geology courses (with students who have background to understand the Nature article).
- Nature Geoscience paper: Nelson & Grand, 2011, Lower-mantle plume beneath the Yellowstone hotspot revealed by core waves
- A Daily Express article about the Nature Geoscience research was provocative in its presentation of possible activity at Yellowstone
- Excellent article that summarizes why Yellowstone won't erupt anytime soon, what hazards are a threat to Yellowstone, and why it should not be called a "supervolcano": EOS by AGU, "Don't Call it a Supervolcano"