Monday, July 28, 2008
Friday, July 25, 2008
What I always had trouble with was visualizing the subsurface well enough to create the cross-sections. The area we were mapping ("Pandora", for my class) wasn't just underlain by a nice neat series of tilted sedimentary layers, nor did the cross-sections cut perpendicularly across them. There was much calculating of angles and hand-waving, accompanied by experiments with Play-Doh. I always had difficulty with the math, and I used to spend a lot of time trying to draw the subsurface in 3D, or create Play-Doh reconstructions, so I could visualize the connection between the structure measurements, surface patterns and what was supposed to be happening below the surface. Pandora was a major undertaking, and it is with great satisfaction that I displayed the final map on my wall.
Which is why, when I saw Andrew Alden's post about a new tool for teaching structural geology, I was quite excited. Dr.
Here's her description of the new cubes:
"A cube made of white opaque high-density plastic, which serves as dry- (or wet-) erase material, makes teaching and learning three-dimensional geology much easier and fun. Maps, cross sections and block diagrams can be drawn (and erased!) and seen in three dimensions, and compared with their two-dimensional projections on paper. For example, the cubes are very useful for teaching the concept of apparent dips, which is essential in the construction of cross sections and block diagrams, and is confusing to many students. Plotting apparent dips on block diagrams is especially difficult, because of the distortion caused by the projection. The dry-erase cube provides an intermediate step. Students can first draw the actual apparent dip on the cube and subsequently construct the same angle on the projection of the block on paper. This can be made especially easy if the edges of the cube have the same length as the edges of an isometric block diagram on paper, so that they can simply be lined up.I'm quite excited to see something like this, not only because it will make my life easier, but because I'm going to shortly be TAing for intro geo labs. Geologic mapping is a difficult skill to acquire for even the geologically-inclined, and for a generation of people who have grown up with Mapquest and talking GPS units, it's also a very important skill. If you can handle a geologic map, then you can handle a regular old road map, which is an ability that's becoming rarer and rarer nowadays. Hopefully, having one of these cubes will make it easier for me to explain the connection between surface patterns and the underlying geology of a region.*
"Several dry-erase cubes can be placed adjacent and on top of each other, so that multiple levels of maps, and parallel and perpendicular cross sections can be constructed. The relationship between maps and cross sections is then clearly visible. The cubes are also an aid in the understanding of stereographic projections, because structural data can be made visible as three-dimensional planes and lines before they are plotted. The dry-erase cubes are not only useful for geoscience teachers, but or anyone teaching or dealing with geometries and block diagrams, e.g. engineers and mathematicians, geologists in the petroleum or mining industries, hydrologists and K-12 teachers."
The dry-erase cube are currently being published in the newest issue of JGE:
Kuiper, Y.D., 2008. The dry-erase cube: making three-dimensional visualization easy. Journal of Geoscience Education v. 56, n. 3, May, 2008, 261–268.
*Only if I can brush up on those drawing skills, though!
Tuesday, July 22, 2008
While I was at the Boston NSTA meeting, I ha d the chance to meet a fellow from the Southern California Earthquake Center, and chat with him a bit about the Center's work. I was really impressed by their public awareness campaign (which has a slogan of, appropriately, "Shift Happens", in addition to Dare to Prepare). It often seems to me like the US is poorly prepared even for natural disasters that happen more often than major earthquakes (any number of hurricanes, floods, tornadoes and fires come to mind), but outside of a few areas o f the country, hardly anyone is prepared for earthquakes.
The Great Southern California ShakeOut is a fantastic idea, but it needs to happen in other places than California. The Pacific Northwest, sitting on a subduction zone capable of producing 9+ magnitude earthquakes, is especially at risk, as well as the entire Midwest (which could experience another New Madrid quake) and even the East Coast (where Charleston was once the site of a ~7 magnitude quake). While the recurrence interval for quakes in the eastern US is certainly much longer than elsewhere, major quakes can - and do - happen. And when they do, very few people will be prepared in any way whatsoever. That's why the ShakeOut is a great opportunity for the entire country to get involved in an earthquake drill. Even if it's something as simple as securing heavy shelves to the wall (a good idea anyway), mapping out a route to get away from urban centers, putting together an emergency kit, or stocking up on bottled water and canned food, get involved!
Here's the info from the ShakeOut website:
"The Great Southern California ShakeOut is a week of special events featuring the largest earthquake drill in U.S. history, organized to inspire Southern Californians to get ready for big earthquakes, and to prevent disasters from becoming catastrophes. An Earthquake Drill for the Record Books
"At 10 a.m. on November 13, 2008, millions of southern Californians will “Drop, Cover, and Hold On.” Why? An enormous earthquake is in our future, and the ShakeOut Drill is our chance to practice what to do when it happens. Individuals, families, businesses, schools and organizations will join firefighters, police officers, and other emergency responders (involved in the statewide “Golden Guardian” exercise) in our largest-ever earthquake preparedness activity. Don’t miss out!
"ShakeOut is based on a potential 7.8 magnitude earthquake on the southern San Andreas Fault. This type of earthquake occurs in southern California every 150 years on average, and the last was 151 years ago! Dr. Lucy Jones of the U.S. Geological Survey has led a group of over 200 scientists, engineers, and others to study the likely consequences of this enormous earthquake in great detail.
"In summary, the ShakeOut Scenario estimates this earthquake will cause some 2,000 deaths, 50,000 injuries, $200 billion in damage and other losses, and severe, long-lasting disruption. The report has regional implications and is a dramatic call to action for preparedness, and is available at www.ShakeOut.org."The ShakeOut includes these main events:
- ShakeOut Drill (Nov. 13)
- International Earthquake Conference (Nov. 12-14: Presented by the City of Los Angeles - iec.lacity.org)
- Golden Guardian Emergency Response Exercise (Nov. 13-19: Emergency mangers, fire fighters, and other first responders will practice how they will respond to this large earthquake -
- Los Angeles Earthquake: Get Ready Rally (Nov. 14: designed by Art Center College of Design)
- Take One More Step (Nov. 14-16: community activities to promote additional preparedness.)"
("Shift Happens" makes a fantastic bumper sticker, by the way.)
Sunday, July 20, 2008
I'm not sure if I'll be able to post while I'm there, but I'll be back with fantastic volcano photos! In the meantime, I'm going to set up a few posts to go live while I'm away. Comments may be delayed until I get back home, but feel free to post 'em anyway.
And, back on its regular Sunday schedule:
Thursday, July 17, 2008
Thanks for all the compliments, by the way - I hope they're as fun to read as they are to make!
Wednesday, July 16, 2008
Monday, July 14, 2008
"The new series will highlight the delicate balance of life on the planet and how its history has lurched between disaster and recovery."I watched the "Volcanoes" episode, which is described on the National Geographic website as follows:
"Volcanoes are one of nature’s most awesome and destructive forces, but they are also the life force and architect of our planet. They can raise up great mountains and create new land, or they can level cities and destroy entire civilizations. They provide a glimpse of the power of Earth’s internal heat source, without which it would have become a dead planet millions of years ago. In this episode, Iain takes us on a journey to some of the most dramatic places on Earth, starting in Ethiopia."
On the plus side, "Volcanoes" featured some really spectacular photography. The episode begins on the slopes of the Erta Ale volcano in Ethiopia, which is the site of a famously long-lived active lava lake (it's been around since at least 1967). Dr. Stewart does what any good crazy geologist would do - rappels over the edge of the outer crater and makes his way as close to the inner crater edge as possible, where we (somehow) get so see some wonderful "flyover" shots of the lava lake. The footage is really beautiful, although I hope the cameraperson had a really long telephoto lens for some of those shots. The rest of the episode is equally well-filmed, with a number of great aerial and satellite images as well as very good groundwork (my personal favorite being a shot of an erupting Icelanding geyser that's perfectly lined up with the sun overhead).
The show makes a pretty dizzying series of jumps to different places around the world - Ethiopia, Iceland, Pakistan, New Zealand, South Australia - but shows off a number of geologic locales that don't usually get a lot of visibility. I was pleasantly surprised to see Shark Bay in Western Australia featured in the discussion about volcanoes and the early Earth, and Thingvellir in Iceland in a segment about mid-ocean ridges. The field trip Dr. Stewart took to a South Australia outcrop containing Ediacaran fossils was very neat, especially the clever use of Silly Putty to make the fossils more visible without damaging them.
While the views and localities are definitely worth seeing, the narration is very light on science. Dr. Stewart discusses the basic ideas behind plate tectonics and convection, and is (thankfully) very careful to say "hot rock" instead of molten rock, but then the focus skips away from volcanoes and settles on tectonic mountain-building processes. For several minutes we hear about how mountains are built through collision tectonics and then eroded by weather and water, but there is absolutely no tie-in of volcanoes - indeed, there are several opportunities for discussing how "subduction volcanoes" build mountains that are completely passed over in favor of flyovers of the European Alps and (I believe) the Southern Alps in New Zealand.
Another disappointing aspect of the show is that there are very few interviews with specialists. While Dr. Stewart is certainly a qualified geoscientist himself (he currently lectures at the University of Plymouth, and he's been a lecturer at Brunel University and the West London Institute of Higher Education in the past), his narration is very broad and shallow. Two interviews are presented in the course of the hour - neither with a volcanologist - and while one does touch on the role of volcanoes in fostering life in geothermal springs and undersea vents, the other interview is with an expert on the Cambrian explosion, and concerns fossils. Granted, the show's focus is on the interaction between life and geology, but it's a little strange that the producers chose not to avail themselves of all the volcanological experts out there for an episode on volcanology. (They didn't even bring out Don Swanson, who's practically a fixture for popular science programs on volcanoes.)
I was equally unimpressed by the animations. I've been watching programs like this for a long time (all the way back to reruns of the PBS Planet Earth series that came out in 1986), and the animations in this one were pretty underwhelming. They were overly-simplified and, if Dr. Stewart hadn't been so careful to note the difference between hot rock and magma, could have been misleading. I much prefer the ones that appear in the recent Faces of Earth series, which also gets my vote for better science content and interviews. (Faces of Earth occasionally runs on the Science Channel, but can be purchased through the American Geological Institute
I found the attempt to link geology and the evolution of life a bit confusing, and frankly clumsy. There was a little too much discussion about how "amazing" it was that volcanoes and life were "able to fine-tune" atmospheric CO2 levels, for example. While it's true that there is a global cycle involved (CO2 is emitted by volcanoes, trapped by biota, captured in ocean sediments and then returned to volcanoes by subduction), it's misleading to describe the process as if there was any active intelligence involved on the part of the volcanoes or the plankton. In reality, the biologic elements adapted to the conditions created by the volcanoes; much as we like to anthropomorphize things, it's simply not appropriate for a geological discussion. The portion of the episode where hot springs and geothermal vents are pointed out as the probable locations for the origins of life does actually come up at a logical point, but some of the other instances where life and geology are linked seem slapped-on, like the producers couldn't decide what kind of focus the show was supposed to have. It made for a very disjointed progression, without a good flow of ideas and easy-to-understand linkages between concepts.
Ultimately I would recommend the series for its cinematography, which was excellent, but I was let down by expectations that it would be a more in-depth version of the Hot Rocks show. Even for a casual audience, the science was sparse and terse, thrown out in little tidbits that seemed more like photo captions than anything else. And while it's certainly fun to listen to Dr. Stewart (since he is an engaging speaker, and I think he has a neat accent), and I'm sure he had a great time getting to visit all the beautiful locales, it doesn't make up for the fact that there's more geological eye candy than content in the epsiode I watched.
Friday, July 11, 2008
Yep, my brain is toast today. I do, however, love this thing. It's the perfect time-waster for a volcanologist.
Sunday, July 6, 2008
The uniqueness of blue quartz is due to properties that are uncharacteristic in ordinary quartz, opalescence, chatoyancy, and asterism. In addition, all blue quartz specimens are highly fractured and contain inclusions of rutile or other minerals.Blue quartz has an opalescent or "waxy" (according to them) luster, which is changeable ("chatoyant") depending on the light. Asterism is defined as the "illusion of a star-like figure" in a mineral, and seems to show up in photomicrographs of blue quartz.
There are several things that can cause quartz to look blue. The first is the presence of inclusions that scatter visible light in the blue part of the spectrum - usually zoisite, tourmaline and rutile. The blue color may also come from closely spaced, subparallel microfractures, which are found in all blue quartz samples. Finally, it has been suggested that the presence of titanium (in the form of rutile or ilmenite) could cause the blue color, although there are specimens of blue quartz with no titanium, and quartz of different colors that contains large amounts of titanium.
Here's the photo from a 2002 Virginia Minerals (from the rock garden in front of their building in Charlottesville):