Eruptions problem set
The following is a problem set that will allow you to explore the various monitoring datasets that are used at Kilauea volcano. I am more interested in you being able to get a grasp of what instrumentation is deployed, what it measures, why it is important, and how the various measurements work together to give scientists a picture of the overall state of the volcano. I am less concerned with you being able to define each bump and wiggle that you might see. So think big picture when you look at the tilt, rsam, and gps data.
Kilauea Volcanism Problem Set
The goal of this problem set is for you to:
- read a report detailing recent eruptive activity at Kilauea volcano.
- predict hypothetical instrument responses to certain volcanic activities
- calculate the rate of magma movement based on measured seismicity
- use tilt, GPS, and RSAM data to describe an eruptive event at Kilauea.
Part 1, reading and questions
Read this paper, available through Library e-Reserves. This paper is a report of some sustained eruptive activity that occurred on Kilauea and its East Rift Zone during the summer of 2007. The activity was recorded by a wide variety of geological, geophysical, and geochemical monitoring instruments, the details of which are discussed in the paper. If you are unfamiliar with any or all of the types of instrumentation described, this paper may seem dense. My advice when reading is to try to focus on the space-time sequence of events, rather than the specifics of the instrumentation. In addition, you may want to go back one page in this lesson to refresh your memory of what each type of instrument measures. Perusing my follow-up questions first will help focus your reading.
Poland, M., A. Miklius, T. Orr, J. Sutton, C. Thornber, and D. Wilson, 2008. New Episodes of Volcanism at Kilauea Volcano, Hawaii, Eos 89, 37-38.
Answer the following questions. Append them to the same document you started for the eruptions problem set that dealt with the VOGRIPA database.
- Look at Figure 2 of Poland et al., 2008. Find the summit caldera. Find the three instruments UWE, UWEV, and AHUP. UWE is a tiltmeter. UWEV and AHUP are GPS stations. If the summit were inflating with magma, would you expect UWEV and AHUP to get closer together or farther apart? Why? If the summit were inflating, in what direction would UWE tilt? Why?
- This question is just hypothetical! It is not directly related to the paper you read. Draw a sketch of the expected signal during a hypothetical summit caldera inflation and subsequent eruption. The blue sketch below shows the hypothetical caldera for this problem. A and B are both GPS stations and C is a tiltmeter. The triangle is the caldera summit. On the blank axes, time is on the x axis and distance is on the y axis for the GPS signal. Time is on the x axis and angle is on the y axis for tilt. The vertical dotted lines mark the beginning of caldera inflation and the beginning of the eruption. To make your drawing, download the drawing tool as a jar file. Alternatively, here is a windows64 version of the drawing tool. Here is a windows32 version of the drawing tool. In the drawing tool, drag the mouse to draw. When you are done, press the button in the top left corner to save your plot. Paste the plot into your problem set document. I am not looking for correct units, this is just a sketch.
- Calculate magma flow speed based on earthquake locations given in the bottom panel of Figure 3B of Poland et al., 2008. Speed should be calculated over the time period spanned by the episodes labeled T1 - T5. Note the scale bar of 1 km given in the lower corner of the plot. When you write your answer to this question, please lead me through your logic. You will have to make some choices about how to estimate times and distances, and I want to hear your explanation of how you chose to do this.
Part 2, analyze and interpret real data from the June 27 eruption at Pu'u O'o
The data that you need to complete this part of the problem set is located in three spreadsheets in CANVAS. It is downloadable from the Lesson 6 module.
If you skipped Reid Townson's animations on the previous page, now is a really good time to go back and look at them! Also you may want to read the description of a deflation-inflation cycle at Hawaiian volcanoes. This description explains how tiltmeters and GPS record what is going on at the volcano and has some cartoon cross-sections of what the volcano is doing.
There was a fissure eruption that began in June 2014. I want you to use GPS, tilt and RSAM data to describe it. Note that you will have to go to Canvas to download the data, which is in Excel spreadsheets. You will have to decide how to visualize, analyze, and interpret this data, with some guidance from me. This is part of the real fun of using real scientific data that hasn't been sanitized for "educational purposes"! Post to the Questions discussion board if you get stuck!
Use the maps of instrument locations on the previous page and the data recorded by those instruments to answer the following questions about the eruption:
- The RSAM station is station STC. Where is this station relative to the Pu'u' O'o vent?
- The tilt station is PUOC. Where is this station relative to the Pu'u O'o vent? If the magma chamber under Pu'u O'o were inflating, describe what the tiltmeter would be doing.
- The GPS data is given to you as the distance between the two stations PUOC and JCUZ. Where are those two stations in relation to Pu'u' O'o? Would they be getting farther apart, closer together, or staying the same distance apart if the magma chamber under Pu'u O'o were inflating?
- The RSAM and tilt data cover two months' worth of time whereas the GPS data is for a whole year. But which files are bigger and why? What implication does this have for how precise your answers might be later on in the problem set if I ask you to look at all three types of data at the same time and discuss what is going on?
- Let's explore the RSAM record first. Make a plot of the RSAM data and include it in your problem set. A scatter plot is probably what you want. Put time on the x axis because this is time series data. What time period does it cover? What is the "normal" amount of seismic activity recorded on a normal day at STC? There is a huge peak in RSAM. Find it and tell me when it happens and how big it is relative to what you decided was normal.
- Now let's take a look at the tilt data. Make a plot of the tilt data and include it in your problem set. What time period does it cover? There are two components of tilt measured at the same time at this station, called "radial" and "tangential." These two components are perpendicular to each other. Both of them have big excursions from their initial values. When does that happen? Describe the changes for each component. Knowing what you know about how tilt is measured and having just described what the two components instruments measured, tell me how each component is oriented with respect to the magma chamber.
- Onto the GPS data! Make a plot of the GPS data and include it in your problem set. What is the approximate rate of change of the distance between PUOC and JCUZ between January and April 2014. What I am asking you for is a velocity. Are PUOC and JCUZ getting closer together or farther apart, and how fast is this happening? Pay attention to the units.
- Sometime later than April 2014, there is a sudden big change in the distance between PUOC and JCUZ. When does it happen and how big a change is it?
- Look at the GPS data that spans Sep - Dec 2014. Has the magma chamber resumed what it was doing during January - April, or is it behaving differently now? Explain why you think so.
- Using all three types of data, tell me the story about what was happening at the volcano during 2014. What I want here is for you to synthesize your answers to the first seven questions into a coherent story explaining what happened at the volcano and how you know it from the instrumental evidence. A few sentences or a short paragraph will do.
- Find maps and photo/video records that correspond to this eruption. Does this additional information confirm your description of what you thought was happening physically? If so, lead me through a what you see and how it correlates to the instrument records you described earlier. If not, discuss possible reasons why not.
Submitting your work
Upload the document containing both your earlier work from VOGRIPA and the work you just did with Kilauea to the eruptions problem set assignment in Canvas by the due date specified on the first page of this lesson.
I will use my general grading rubric for problem sets to grade this activity.