Posts Tagged ‘volcanoes’

My PowerPoint lecture notes started coming together when I taught for the first time back in 01-02.   At that point, textbooks did not give you access to digital versions of their figures, so I spent quite a bit of time cruising the internet looking for appropriate pictures & diagrams.   Quite a number of those original photos had sketchy to nonexistent place labels.   Over the years, I’ve replaced tons of these photos with ones I’ve taken, digital figures from textbooks, and just better random images from the internet.   I try hard to know where the image was taken, since the students seem to enjoy knowing that this one is from Hawaii or that one is from Mt. Etna.

This morning, I was going through my volcanoes lecture and one of the cinder cone pictures has a comment on it of “Mauna Loa? Haleakala? Somewhere completely different?”   Amazingly enough, the original image is still up on the web, but there’s no obvious label on it.   I believe it used to be labeled Haleakala, but all the other pictures on the page were from the Big Island & its url has “Maun” at the end, so I was skeptical about the label.   Can someone help me out?   Have you seen this place “live”?

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(I’m still catching up with some of activities we did over the past few weeks.   This one was done during the first week of class while we were discussing magma / lava properties.)

I went searching at the SERC site for a viscosity experiment demonstration and found one by Ben Edwards written for a petrology class.   Since my class didn’t have that kind of background, I changed the assignment some to make it more simplistic (removing the math & compositional links).   I wasn’t really sure how well this was going to go, but it turned out to be one of the best assignments I’ve ever downloaded from the SERC site.

I’ve posted my notes, handouts, and logic over on my Google site.   But I’d like to post pictures here.

Basic setup:

  • use a tilted large wooden board covered with wax paper as our flow surface; whole set-up on top of an old plastic shower curtain for easy clean-up
  • have 9 different corn syrup preps to pour down the board to record things like: how long does it take to get to the bottom; shape of the flow; width of the flow
  • before pouring them down the board, we blew bubbles in the corn syrup with straws to determine how easy / hard it was to do, what the bubbles looked like, and how quickly they moved to the surface

All in all?   Great set of experiments that the students got into & maybe more importantly, still remembered which ones and gone faster / slower and easier / harder for the bubbles to move several weeks later.   High recommendation for this activity if you want to teach about viscosity.

Amy blows bubbles in the "cold" experiment while Todd looks on

Emily pours the mix with lots of couscous (ie crystals) down the board

run with lots of water got the bottom before any of us were really ready :)

the cold one took forever to get to the bottom

we had plenty of time to sketch & take pictures with the cold one

the cold one also had the most interesting morphology at the bottom

beginning to wonder if it was ever going to get to the bottom line...

part of it finally crossed the line... this one was no issue to get into the trash before it ran off the wax paper onto the shower curtain 🙂

the warm one got to the bottom before Emily had even stopped pouring!

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We’re at the portion of the Iceland class where we’re going through the history of the island nation and talking about what kind of volcanic activity occurred at specific times & the impact it had on the society.   I have a few activities to fill in that we did, but I was reading a Science article about the 1783 Laki eruption (Stone, 2004, Iceland’s Doomsday Scenario?: Science, 306, 1278-1281) and at the end of the first column they talk about what would happen if a similar sized eruption happened today:

A similar blast in modern times would pump so much ash and fumes into the upper atmosphere that the ensuing sulfuric haze could shut down aviation in much of the Northern Hemisphere for months, Thordarson and Stephen Self of Open University in Milton Keynes, U.K., argued last year in the Jour- nal of Geophysical Research.

“It’s not a matter of if but when the next Laki-like eruption will happen” in Iceland, says Thordarson, who splits his time between the University of Iceland and the University of Hawaii, Manoa. “We certainly don’t want to be here when another Laki- type event hits,” adds Self.

There are days when geologists look awfully smart 🙂   I just wanted to share.

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Due to the complexity of the corn syrup viscosity experiments, I’m going to come back to that activity later.   Instead, I’ll skip ahead to my next GoogleEarth file.

This kmz is fairly simplistic: I simply cruised through the Global Volcanism Project looking for a variety of volcanoes with different structures.   There is a kmz file of all the volcanoes within the GVP database, which can make them easier to find, but you sort of have to hope your students don’t find it since it includes all of the answers.

The students then have to determine whether the volcano is a dome, stratovolcano, shield volcano, cinder cone, or a maar.   For a few cases, I added a few hints to help the students understand they were looking at a cinder cone and not the shield volcano it was on.   For some of the cases, I also asked the students to distinguish whether it was a crater or a caldera.

Ways this might work better:

  • take a collection of Erik’s Mystery Volcano pictures and ask them to identify the structures – would cut out the ability to simply use the GVP database
  • add a fissure or two into the mix
  • find a better maar (I think it may be mislabeled on the web… but I wasn’t sure)

Suggestions on volcanoes I should include?   Ones I should avoid?   How this might be a better assignment?

And, as of 30 minutes ago, this assignment is up on my Google site including the kmz.

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(I want to thank Erik Klemetti for coming out to snowy MN and giving a great talk yesterday.   If you’re considering bringing in a speaker in the next semester and want someone who will give a good talk that is understandable by a broad range of people on campus, invite Erik.)

I’m going to backtrack a bit and post about the activities that I ran last week during the first section of my Iceland course.   Some of these activities were entirely designed by me, but most were modified after searching through the SERC database.   If you haven’t had the chance to look through the selection of teaching & lab activities as well as course outlines and pages about various analytical methods, they are a wonderful resource for anyone teaching geology.

The first day of lecture started with a GoogleEarth assignment looking at various plate tectonic settings.   This assignment is one I made up while teaching Earthquakes & Volcanoes at UPJ and simply tweaked for my Iceland class.   I do the lab activity pre-lecture, so that the students get to “observe” things like change in depth around a mid-ocean ridge vs. a convergent margin, relationship between trenches & volcanoes, and age vs. location in the ocean.   I have a sequence of leading questions that I ask about placemarks in a kmz file that the students load into GoogleEarth (previously I gave lat / long, but the placemarks work better).   I have them look at three different ridges, trenches, and a single hotspot track (Hawaii).   I tried for a variety of divergent & convergent zones to highlight the fact that they can vary in width, length, and depth.   I’ve also included a few overlays from GeoMapApp (free program that has just been updated & is great for teaching), since you can save specific datasets (e.g. age, bathymetry) as kml files.

Once the students had worked through the assignment (took about an hour), I then gave a very, very short “this is what a divergent, convergent, transform, and hotspot track are” lecture and we did a gallery walk (you hang pieces of paper on the wall with titles such as “divergent” “convergent” and then in small groups the students write down one property / fact about that title then move onto the next piece of paper).   The students did a good job of translating what they had seen in the GoogleEarth activity to the characteristics of the different plate settings, which was reassuring.

I’m still thinking about playing with the assignment more before I upload my activity to SERC, but if you’re interested in my kmz file & questions, please leave me a comment.

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(The silence is mainly due to working.   pre-GSA I was prepping to get everything done before jetting over to Denver.   Once I returned, I had to catch up from GSA.   Altogether, that means I’ve been spending the majority of my time grading, writing lecture, prepping field trips, and kicking my pseudosection models.   I just gave one midterm in petrology and intro has one on Monday, so the grading is not nearly over.   But, I want to start to catch up on blogging.)

Week #8 for the geology news journals was 24. – 30. October.   In case you forgot, that was the 7.7 magnitude earthquake off of Indonesia, the resultant tsunami, and an unrelated eruption of Mt Merapi.   It was not a good week for Indonesia.

Of the 56 submissions I received (yes, I have 70 students in the intro class…), all but 5 dealt with one, two, or all three of the events in Indonesia.   Unfortunately, there were a few “common” misconceptions that either my students borrowed from the news articles or inserted themselves into the summaries:

  • misconception #1 – the earthquake caused the eruption of Mt Merapi; Jessica over at Magna Cum Laude dealt with this one very well earlier this week, so I’ll let her present the scientific reasoning
  • misconception #2 – the USGS reports all of the earthquake sizes on the Richter scale (as a side note, this has been coming up a few entries per week, but we haven’t gotten to EQs yet in lecture for me to talk to the whole class about it yet); the Richter scale was developed in the 1930’s by Richter & Gutenberg at CalTech to specifically measure by the amount of energy (the local magnitude) released by an earthquake for regions in California by looking at ground movement.   Different rocks will react differently to seismic waves depending on what they’re composed of & their current temperature, which means you can’t use the same local energy scale for different places on the Earth.   For instance, seismic waves on the west coast go through warmer rocks and therefore are slower & diffuse quicker than seismic waves through the cold east coast rocks.   When an earthquake happens in LA, it doesn’t ring church bells in San Francisco (380 miles), but in 1886 an earthquake in Charleston, SC rang church bells in New York City (800 miles).   The Richter scale is also only appropriate for earthquakes with a magnitude less than about 7.   What we now use in the world is a magnitude moment measurement, which was developed in the 1970s (by Hanks & Kanamori–also from CalTech!).   Though moment magnitudes are not appropriate for small earthquakes (<3.5), it has no upper end and will be appropriate for all rock types & temperatures.   The calculation is based on properties of the rock where the rupture occurred, the area of the rupture, and the average amount of displacement that happened.

The second point will be part of my discussion of earthquakes in the coming weeks, though it wasn’t something that I even understood well until I started teaching introductory earthquakes & volcanoes.   I have no idea whether its even a topic in my Marshak textbook–which is currently at work (I’m at home due to a rather large sudden snowstorm in St. Peter today).

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