The average American gopher, weighing roughly 1-2 lbs, lives a solitary life in a burrow consisting of multiple tunnels. Whether used for foraging, storage, or rest, these tunnels can reach up to hundreds of square meters in size, with depths ranging up to 1.8 m (Bradford 2017). With an assumption that I can consider myself an average America, this feat is more than I expect to accomplish in my lifetime (Minecraft excluded).
Figure 1. Gopher, ft. burrow (Credit: Bradford 2017, originally from National Park Service)
Debatably more accomplished than a gopher, the Earth has created tunnels through a plethora of processes. Lava tubes and their formation are the most applicable process to my research. Generally seen as a “roofed conduit” of actively flowing, drained, or plugged magma, lava tubes on Earth range from meters to kilometers in length, 0.5-30 m in width or height, and anywhere from centimeters to meters in depth below the surface (Sauro et al. 2020). Now this may feel like it puts the gopher’s efforts to shame, but a little perspective and googling will tell you that Earth weighs around 13.17e24 gophers (Cool Cosmos, IPAC). Even more shameful is the fact that Lunar and Martian lava tubes have been found to be 10-1000 times more voluminous than those on Earth (Sauro et al. 2020). As of the writing of this blog I do not know of any gophers having conducted interstellar travel.
Volcanoes’ process of digging is a degree more heated than gophers’, with the three main mechanisms being overcrusting, shallow inflation, and deep inflated-entrenched tubes. Overcrusting of magma occurs when the outer surface chills and solidifies, insulating the molten lava below and allowing it to maintain a high temperature and low viscosity for longer, and thus farther from the vent. Shallow inflation results in a superficial bulge morphology; for pahoehoe lava flows this bulge forms along the tube's development and the process revolves around uplift of the lava sheet. Elliptical tubes are then formed and can become open after drainage. In juxtaposition, the shallow inflation bulge for a’a flows is found nearer to the end of the lava flow, and due to higher pressure from a form of “stoppage”, a’a flows create larger lava tubes. A step higher, deep inflated-entrenched lava tubes are among the largest found on Earth and involve downward thermic erosion and breakdown. [Sauro et al. 2020].
Figure 2. Models of lava tube formation processes (Sauro et al. 2020). Of note are A corresponding to overcrusting, C to pahoehoe shallow inflation, D to a’a shallow inflation, and E to thermal erosion and breakdown.
Definitions of technical jargon aside, lava tubes (inferred from the presence of skylights and collapse on sinuous features) on the Moon and Mars were created through similar processes; overcrusting and shallow inflation for Mars, and deep inflation-entrenchment for the Moon. Unfortunately for Mars, lunar lava tubes are the current candidate for the most likely to be stable award (Sauro et al. 2020). Fortunately for Mars, my research into modelling lava tubes using mesh and seismic wave propagation software looks past this shortcoming. At its current stage, my research focuses on using mesh software (such as GMSH) to create lava tube analogous geometries. My next step is to import this mesh geometry into SPECFEM2D, a spectral-element solver that will allow me to simulate the propagation of acoustic (seismic) waves through the medium (SPECFEM2D 2020). A step not taken by your average American gopher.
Figure 3. Example of a simple lava tube mesh geometry (created by me using GMSH software).
References
A. Bradford. Facts About Gophers, Live Science (2017),
https://www.livescience.com/57623-gopher-facts.html
Cool Cosmos. How much does Earth weigh and how is this measured? IPAC.
https://coolcosmos.ipac.caltech.edu/ask/61-How-much-does-Earth-weigh-and-how-is-this
-measured
F. Sauro, R. Pozzobon, M. Massironi, et al., Lava tubes on Earth, Moon and Mars: A review on
their size and morphology revealed by comparative planetology,
Earth-Science Reviews (2020), https://doi.org/10.1016/ j.earscirev.2020.103288
SPECFEM2D User Manual (2020). https://specfem2d.readthedocs.io/en/latest/
A really interesting topic, with elements that reach out to the general audience (gophers), but quickly devolves into a lot of jargon. This will be important in later products for the class, but here you want to be talking to your grandmother. Let's think about your word choices, and not worry so much about the details of your project in this blog. There is no need for citations here, except perhaps in links at the end.
ReplyDeleteGophers are cute! This metaphor makes lava vivid. I always find it difficult to introduce calculation models to others, especially to those who never touched computing. Sometimes it is also difficult to understand others' calculation work, because we use different softwares and methods. It might be a challenge for you to rewrite the last paragraph to make it easy-to-understand (for your grandma) while keeping the scientificity. I'm looking forward reading your amendment, especiaclly for the last paragraph. What's more, I can get that you tried hard to make the last figure simple, but forgive me I still can't immediately catch the meaning of this figure. (Maybe because it's too simple?)
ReplyDeleteI love the tone you used throughout the post - it's very conversational and made me want to keep reading along. The terminology gets a little complicated about halfway through the third paragraph, but everything before that sounds great! When it comes to discussing the work that you're doing, I would make sure to simplify it as much as possible. For example, even though I'm a geologist (kind of), I have no idea what mesh means in this context. Also - I think it would help to find a less technical version of figure 2. It has really good info in it, but is a bit too cluttered for a blog post.
ReplyDeleteHi Linden! This is a great blog for geologists who want to learn about lava tubes but lacks background knowledge (me). The gopher analogy helped me understand the structure of lava tubes. I agree that halfway through the third paragraph the language gets complicated. I liked how you incorporated your own research. In class when you were explaining your mesh software, you said something like “it’s a box with a circle through it and the circle is the lava tube” which helped me understand your modeling better.
ReplyDeleteHi Linden, I really liked how you introduced your blog. I think the fun tone at the beginning can help draw in a general audience and the metaphor between lava tubes and gopher holes is super visual and easy to wrap your head around. I like your figure of the different ways lava tubes form, but I do also think you could maybe take off the labels and maybe only show the three you talked about to simplify it a bit. I also liked how you introduced your own research but maybe explaining in everyday language what a mesh is would help a general audience.
ReplyDeleteI really appreciated your gopher narrative hook, and that you kept returning to it throughout. I did get turned around in your discussion of the mechanisms that form lava tubes. I think it is important to discuss those, but I would suggest slowing that section down and explaining things in a bit more detail. Be sure to explain terms, even just in passing (for example, I know it's basic but I can never remember the difference between the two types of lava). Otherwise I thought it was an interesting post.
ReplyDeleteHi Linden! Nice blog! As mentioned by other classmates, the text gets a little technical after the third paragraph. Maybe you should use another picture for the explanation of lava tube formation types, especially for the last two mechanisms, that could be helpful. Also, I think that your research is very interesting and I can imagine the objective of your study (I came from Casey’s blog), but I am not completely sure, maybe you can mention why it is important to know about these lava tubes in Mars?
ReplyDeleteBy the way, I loved gopher's analogy.