VEPP: Using volcano deformation data for lava flow hazard assessment and decision making, Part II: Past is the key to the future
Summary
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.
This is the second part of a loosely linked three part activity. Each part can be used as a stand-alone activity with slight modification. This part focuses on the deformation signals generated by lava outbreaks, whether those signals can be used for accurately predicting where and when lava outbreak events will occur, the factors governing lava flows, and hazards of lava flows based on a case study of destruction of Kalapana Village in 1990
Full length description:
Students break out in small groups. Each group receives a topo map without the lava flows marked on it, and a printout of a DEM image or a shaded relief map for the area around Puu Oo.
Compare the topo map with the DEM image to determine the slope of the area and try to infer the direction of the lava flow in that area. Mark their inferences on the topo map with colored pencil (10-15 minutes)
Next the instructor passes around a JPG image of the 1983-86 lava flow (available from the "HISTORY" link of the VEPP site for that time period). Students get to see how closely their inferences match the actual lava flow.
Repeat the activity for the next eruption 1986-92 and discuss what could be the possible factors controlling the direction of lava flows (topography, volume of lava erupted, temperature, type and viscosity of lava... etc. )
The statistics of each of the historic flows including the volume of each flow are available in the history section of the VEPP site
(Topo map marking, 5-10 minutes, discussion, 10 minutes)
Repeat the activity for the 1997-2007 range. (Topo map marking 5-10 minutes, comparing with real data, 10 minutes)
Next pick individual events for which GPS and tilt data is available (2004 onwards) and web cam data from 2006 onwards. A good start will be to use the webcam movies as guidelines to pick specific lava flow events and then search for geophysical data around those dates/times.
Instructor distributes the tiltmeter and GPS plots for "before" and "after" a specific lava outbreak event. Each group gets a different event to work with.
Instructor provides plots/vector maps showing change in line length from GPS data, change in elevation.. etc.
Students work in groups to identify (if any) indicative trends in the geophysical data that might be used to predict an eruption
Students determine if there is a correlation between the GPS data and tiltmeter data (note: include rainfall data in each tiltmeter data plot and "detrend" them. Tiltmeters tend to drift and move away from the horizontal over time. This gives an overall trend to the data. Detrending identifies and removes the best fit line to neutralize the drift).
The small groups work 10-15 minutes with the data. Then each group reports back with their observations regarding the correlation between tilt/GPS data and lava flow events (report 15-20 minutes).
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Learning Goals
- Students will interpret topographic maps and identify possible paths for a lava flow based on topgraphy of an area
- Students will synthesize past and current lava flow map data (as and when available on the VEPP web site) and predict the likelihood and potential path of a lava outbreak in the immediate future in the Kalapana area
- Students will analyze different types of geophysical data (tiltmeter data, continuous GPS data, and webcam images) available through the VEPP site that were recorded before, during and after specific lava outbreak events, and identify any existing trends or specific characteristics of the data set that can potentially be used for predicting when a lava outbreak will occur
content/concepts goals for this activity
- Lava types (Pahoehoe and Aa) associated with Hawaiian type volcanoes
- Factors controlling lava flow (viscosity, temperature, volume, slope of the ground)
- Specific changes in the volcano that can be measured and potentially used to predict a lava flow outbreak
- Hazards of lava flow
Briefly describe the higher order thinking skills goals for this activity
- Analysis of real geophysical data for identifying volcanic activity
- Synthesis of data collected by different instruments like tiltmeters, GPS, and webcam, and use them for predicting volcano behavior
- Evaluate the errors associated with the data (e.g.instrument failure, rainfall or other factors influencing the data)
- Synthesize the data and their implications in terms of hazard assessment
Briefly describe any other skills goals for this activity
- Collaboration skills for working in small groups
- Quantitative skills such as graph reading and vector addition
- Spatial/map reading skills
Context for Use
This is a studio type activity with a combination of brief lecture/overview/case study, small group activity and large group discussion, followed by a homework assignment
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)?
Small intro lecture (20-24 students) in a 2- year or 4 year college
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):
Lower division undergraduate natural science courses for non-majors (such as natural hazards or volcanoes). This activity can also be used as a module in introductory physical geology course.
Briefly describe or list the skills and concepts that students must have mastered before beginning the activity
At this point students should be familiar with what the geophysical data indicates in terms of different volcanic activities, and uncertainties with data availability and interpretation. This activity will follow a brief discussion of different hazards associated with Hawaiian type volcanic eruptions, focusing on lava flow hazards using the 1990 destruction of the Kalapana Village as a case study.Description and Teaching Materials
Topo maps and shaded relief maps/printout of DEMs showing the general slope and topography of the area. Detailed printout from Google Earth showing houses can add to this activity.
Maps showing the extent of historical lava flows (available on the "history" section, or on the HVO site) for each time section.
Lava flow maps for the current eruption and also for those events shown as web cam movies (if possible)
Tiltmeter and GPS data for specific eruption events resulting in lava flows (E.g., the Father's Day eruption) shown as web cam movies
Teaching Notes and Tips
Accessing the VEPP Web site (https://vepp.wr.usgs.gov) requires a password, which can be obtained by sending an email with your name, affiliation, and intended use of the site to mpoland "at" usgs.gov
The volcanic hazards discussion/case study can be a lecture on that topic during an entire class period, a reading assignment, or can be integrated within this activity as a brief overview/lecture.
Use the "Best Possible" rank as default for GPS data. Always use a baseline station to neutralize the Pacific Plate Motion of the GPS receivers.Assessment
- Each student is assigned a specific time period (hours, days or weeks during the 2010 eruption) for which geophysical data shows evidence of volcanic activity/deformationin general, and lava outbreak events in particular.
- Students access the data, find D-I events from tiltmeter data and determine the time period for each inflation and deflation event.
- Students identify two GPS stations across the Puu Oo vent from the map available on the VEPP "techniques" site, use one site as the baseline and determine overall change of distance (line length change) between those two stations over the specified time period.
- Students predict lava outbreak events based on their data.
- Students download lava flow maps for those time periods (if available) and determine how closely their predictions match real events.
- Students submit a written report summarizing the data, plots and whether or not their predictions were fulfilled, possible reasons their predictions were fulfilled or were incorrect, and uncertainties associated with interpreting real data. This report is graded based on a rubric.