NAGT > Teaching Resources > Volcano Exploration Project: Pu`u `O`o > Activities > VEPP: Volcanic Ground Motion Over Time.

VEPP: Volcanic Ground Motion Over Time.

Rick Dunning
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This is an exercise that is in development and has not yet been fully tested in the classroom. Please check back regularly for updates and changes.

Purpose of the exercise is to help students appreciate volcanoes as dynamic phenomena and illustrate some of the changes that happen physically to the volcano over time as well as how those changes could be measured. That purpose is met by having students monitor and analyze ground motion (Tilt) data recorded by Hawaii Volcanoes Observatory and made available to the students on the VEPP website.

Time can be a surprisingly challenging thing to work within the context of individual lab exercises in a geology course in spite of the fact that so much of the course is focused on geologic processes that operate over time. In the exercise I am trying to take advantage of the capacity of the VEPP web site to display time series data.

I intend to have each student pick two "variables" to monitor that measure ground motion through tilt and have them collect or plot that data over an extended time during the semester (perhaps a month or more). Near the end of the semester we will collectively discuss ways to interpret or analyze time series data and then each student will write a report summarizing their data and analysis. In subsequent discussions I would like them to present their data and together look for connections between the various phenomena that they each studied and talk about monitoring these phenomena for the purposes of trying to predict volcanic activity.

I would also like to have some of these data sets accumulate over subsequent semesters so that students begin to see how these processes operate over still longer periods of time.

Brief three-line description of the activity or assignment and its strengths:

Students will study volcanic ground motion as measured by tilt meters by monitoring tilt data from the VEPP website over a period of 4 weeks. The exercise provides an opportunity to observe volcanic processes over time and explore temporal and physical relationships between volcanic phenomena and, ultimately discuss the potential of monitoring to help predict volcanic activity.

Full length description:

The Lab: Volcanic Ground Motion over Time

You are the vulcanologist. Your job is to find out what's happening on the flanks of Kilauea volcano which has displayed many kinds of eruptive activity continuously for several decades. The USGS is in charge of monitoring many volcanoes throughout the western US. Here you get a chance to use their data from their instruments and find out for yourself.

Volcanoes are dynamic. Molten rock and gases rise from the magma chamber below and erupt on the surface. The volcano itself moves and changes in response to the influx and eruption of lava and gas. That's what you're trying to document. What's happening to the volcano? How is the ground moving? So watch it and find out.

In class we've talked about volcanoes and how they work so now your ready to study a real volcano. The lab activity extends over a 4 Week period but is divided in 5 distinct steps with specific goals for each step. The final lab write-up must address all 5 parts of the activity.

In Step 1 you should choose 2 specific Tilt variables (each variable defined by a station and a direction) from the VEPP website to monitor for the entirety of the exercise. Name each variable and use the information from Techniques section of the website to define each variable, determine how it is measured and what kind of instrument is used as well as where the instrument is located on the volcano.

In Step 2 you should use the graphing capacity of the VEPP website to plot graphs for each variable by itself that show changes in those variables over the same 3-day period beginning with the start date of the lab. The graphs should show how each variable changes. Explain how you think the changes in each variable relate to types of ground motion. For each of the variables, calculate the range of variability. Compare and contrast the two variables Pay close attention to the vertical scales of the 2 graphs - how do the measurement units compare.

Example of Radial Tilt from 2 stations for 2 days:

2 day sample graph

In Step 3 you should use the graphing capacity of the VEPP website to plot graphs of each variable on graphs of identical timescales over approximately a 2-week period beginning with the start date of the lab. Identify ways that the 2 variables change together over that time.

Example of Radial Tilt from 2 stations for 2 weeks:

2 week example

Optional: Extract raw values for each of the variables from the 2-week graphs and produce a new graph that plots the 2 variables against each other. From the graph identify potential relationships between the variables.

At this point the class will discuss volcano dynamics particularly with respect to Inflation and De-inflation sequences.

In Step 4 you should use the graphing capacity of the VEPP website to plot graphs of both variables on graphs of identical timescales over a 30 day period beginning with the start date of the lab. Distinguish trends in the variables that seem to occur over that time. Refer to the updates section of the VEPP website for reports and to the reference section for maps (and perhaps to the HVO website for other information and photographs) from the same time period. List any volcanic "events" (which could be any sort of volcanic activity or inactivity). Identify times where the volcanic events seem to coincide with changes in the variables. Suggest what ground motion might be happening relative to the volcanic events.

Example of Radial Tilt from 2 stations for 1 month:

4 Week example

In Step 5 you should graph the same 2 variables on graphs of identical timescales for the time period beginning with July 1, 2007 and ending with July 28, 2007 which represents "a significant eruptive event referred to by the HVO staff as the Harry Potter event. Describe how the 2 variables change before and during the event.

Example of Radial Tilt from 2 stations:

HP example

Example of 2 directions of tilt from 1 station:

HP example 2

Based on your monitoring of the 2 phenomena (variables), suggest ways that measurements of the 2 variables might contribute to predicting an eruptive event.

In a final lab wrap-up of the exercises students will compare their results in small groups and identify combinations of variables that offer potential predictive capability relative to volcanic activity. A final class discussion will focus on measuring volcanic behavior and on dealing with time-series data.

Learning Goals

Briefly describe the content/concepts goalsfor this activity (e.g., those involving pure vs. simple shear, deformation mechanisms, kinematic analysis, accurate description of samples):

Demonstrate the dynamic nature of volcanoes. Identify some processes of volcanic ground motion and show their variation over time.

Briefly describe the higher order thinking skills goalsfor this activity (e.g., those involving analysis of data, formulation of hypotheses, synthesis of ideas, critical evaluation of competing models, development of computer or analog models):

Analyze data variability illustrated in time-series data. Compare temporal variation of multiple variables. Hypothesize relationships between variations in ground motion and other kinds of volcanic behavior.

Briefly describe any other skills goalsfor this activity (e.g., those involving writing, operating analytical equipment, searching the WWW, oral presentation, working in groups):

Interpreting complex scientific data from original sources. Define instrumentation and measurement techniques used to generate the data.

Context for Use

What is the type of activity (a problem set, classroom activity, lab activity, project, field activity, and/or a writing activity)?

The activity is intended as a lab exercise that will be introduced one week and run for multiple weeks in which student collect data on their own, discussed mid-way through, and discussed again at the end.

What is the class type (small intro lecture, large intro lecture, or UD/grad course; disasters, hazards, field course, or intro geology; with or without computers; community college)?

The class type would be primarily a large intro level lab course potentially with or without computers in the classroom

Briefly describe the type(s) and level(s) of course in which this activity or assignment could be used (e.g., undergraduate required course in structural geology, introductory physical geology course for non-majors, graduate level seminar on geochemistry):

The activity was developed for an intro level Physical Geology lab course. I may also try a similar activity in an intro level Environmental Geology course. And I may consider using the activity in an on-line version of the Environmental Geology course.

Briefly describe or list the skills and concepts that students must have mastered before beginning the activity:

The activity would come at about the mid-way point of the course when students have experience and ability to graph data and interpret graphs. Also, the activity would come after covering volcanism topics in class.

Briefly describe how the activity is situated in your course (e.g., as a culminating project, as a stand-alone exercise, as part of a sequence of exercises):

I would use the activity as a stand-alone exercise though it could work as part of a sequence.

Description and Teaching Materials

Employs the capacity of the VEPP site to generate time series plots.

Teaching Notes and Tips

Please describe any helpful examples of this activity, as well as any potential variations on this theme:

As more kinds of day become available on the VEPP website, the students may have a wider range of ground motion variables to choose from.

What tips might you offer to other educators planning to use this activity?

Instructors should think about posting additional information about the volcano's activity over the course of this exercise - items like new releases and photos from HVO and from web cams. Instructors should also think about posting other measures of ground motion to compare with such as GPS baseline data or perhaps seismic data.

Instructors would do well to stockpile some "canned" data in the event of website or instrumentation problems.


Describe briefly how you determine whether students have met the goals of this assignment or activity.

References and Resources

Please list any supporting references or URLs for this activity:

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