Volcanoes can threaten public safety, water supplies, land, and contribute to temporary climate changes (U.S. Geological Survey, 2018). Canada primarily has volcanic areas in British Columbia and Yukon, but is also exposed to volcanoes along the United States border that may erupt again in the future (Government of Canada, 2020). Volcanoes, therefore, pose a threat to Canadians due to their proximity to cities and vital resources, particularly if there is late detection of the eruption (Government of Canada, 2020). While there are ways to predict volcanic activity, such as GPS and seismic networks and the observation of gas emissions, many of these methods have shortcomings, such as blind spots or delivering warnings close to the volcanic event (Leone et al., 2021). Volcanic muography is an alternative technique that images muons and can provide a system producing numerous warning signs of volcanic activity farther in advance, and is estimated to increase prediction effectiveness by 75%(Leone et al., 2021). In addition, this technology could allow scientists to track changes and movements of magma (Nagamine et al., 1995).
Muons are elementary particles similar to electrons and were proven to exist in 1937 (Street and Stevenson, 1937). The primary differences between electrons and muons are their masses, which is over 100 times that of an electron, and muons’ superior ability to reach and penetrate the ground, as seen in Figure 1 (Street and Stevenson, 1937; Adam, 2021). Muons are formed at great heights in the atmosphere where cosmic rays enter the atmosphere and collide with the atomic nuclei of the various gases present in the air. This crash causes pions, another type of subatomic particle, to form and almost instantaneously decay into muons (Adam, 2021).
Muography operates based on the physical properties of muons as they pass through matter. As muons pass through matter, they lose energy; the more dense the matter in which they are passing through, the more energy is lost (Adam, 2021). When a significant amount of energy from the muon is lost, the muon particle decays into a different subatomic particle, such as an electron (Adam, 2021). Muography uses detectors to track the number of muons that pass through a specified volume; this can give insight into the density of the inner constitution of the observed volume; this setup can be seen in Figure 2 (Leone et al., 2021). Detectors must be put below the volume that is to be observed as muons originate from the atmosphere (Adam, 2021). The tracked muons are then compared to the number of muons that would be observed in the sky revealing which parts of the volcano are dense and which are more vacuous (Adam, 2021).
Muography has been used for various aspects of monitoring volcanic activity. For example, muography allowed scientists to analyze features of the mountain post-eruption. In a study of Mt. Asama in Japan, muography images found that there was a dense region within the mountain, this is shown in Figure 3 (Tanaka et al., 2007). The region was identified as the lava mound formed in the last eruption based on its recorded shape and positioning within the mountain (Tanaka et al., 2007). Additionally, muography has made it feasible for one to observe magma moving through the volcano’s conduit by targeting the mountain’s summit (Tanaka, 2019).
Muography detectors can provide helpful information during the initial stages of a volcanic eruption and for monitoring and analyzing the features of the mountain post-eruption (Tanaka et al., 2009). Thus, muography has essential applications allowing for more preparation and protection of public safety and vital resources against volcanic eruptions.
Resources
Adam, D., 2021. Core Concept: Muography offers a new way to see inside a multitude of objects. Proceedings of the National Academy of Sciences, 118(14), p.e2104652118. https://doi.org/10.1073/pnas.2104652118.
Gibney, E., 2018. Muons: the little-known particles helping to probe the impenetrable. Nature, 557(7707), pp.620–621. https://doi.org/10.1038/d41586-018-05254-2.
Government of Canada, 2020. Where are Canada’s volcanoes? [online] Canada. Available at: https://chis.nrcan.gc.ca/volcano-volcan/can-vol-en.php [Accessed 16 Nov. 2021].
Leone, G., Tanaka, H.K.M., Holma, M., Kuusiniemi, P., Varga, D., Oláh, L., Presti, D.L., Gallo, G., Monaco, C., Ferlito, C., Bonanno, G., Romeo, G., Thompson, L., Sumiya, K., Steigerwald, S. and Joutsenvaara, J., 2021. Muography as a new complementary tool in monitoring volcanic hazard: implications for early warning systems. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 477(2255), p.20210320. https://doi.org/10.1098/rspa.2021.0320.
Nagamine, K., Iwasaki, M., Shimomura, K. and Ishida, K., 1995. Method of probing inner-structure of geophysical substance with the horizontal cosmic-ray muons and possible application to volcanic eruption prediction. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 356(2–3), pp.585–595. https://doi.org/10.1016/0168-9002(94)01169-9.
Street, J. and Stevenson, E., 1937. New Evidence for the Existence of a Particle of Mass Intermediate Between the Proton and Electron. Physical Review, 52(9), pp.1003–1004. https://doi.org/10.1103/PhysRev.52.1003.
Tanaka, H., Nakano, T., Takahashi, S., Yoshida, J., Takeo, M., Oikawa, J., Ohminato, T., Aoki, Y., Koyama, E. and Tsuji, H., 2007. High resolution imaging in the inhomogeneous crust with cosmic-ray muon radiography: The density structure below the volcanic crater floor of Mt. Asama, Japan. Earth and Planetary Science Letters, 263(1–2), pp.104–113. https://doi.org/10.1016/j.epsl.2007.09.001.
Tanaka, H.K.M., 2019. Japanese volcanoes visualized with muography. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 377(2137), p.20180142. https://doi.org/10.1098/rsta.2018.0142.
U.S. Geological Survey, 2018. Which U.S. volcanoes pose a threat? [online] Available at: https://www.usgs.gov/news/which-us-volcanoes-pose-a-threat [Accessed 16 Nov. 2021].
Zhang, Z.-X., Enqvist, T., Holma, M. and Kuusiniemi, P., 2020. Muography and Its Potential Applications to Mining and Rock Engineering. Rock Mechanics and Rock Engineering, 53(11), pp.4893–4907. https://doi.org/10.1007/s00603-020-02199-9.
Comments
11 Responses to “Magical Muons and Magma Movement”
Hi everyone! I decided to research this topic for my blog post because of its relevance to course concepts in our history of the earth modules. While reviewing the mechanism of volcanic eruptions, I researched the current methods for monitoring volcanic eruptions and came across muography. I thought it was quite interesting as I had never heard about it before and most of the papers on it were very integrated with other disciplines. Looking at both imaging techniques using subatomic particles and the flux of magma within mountains was an intriguing perspective for understanding how geophysical processes work and how they can be monitored.
I hope you enjoyed this post!
Paige
Hello Paige,
I found your blog post to be very fascinating, and I love how it relates to science concepts we are learning in hotE. I have a few small suggestions for improvement:
1.In your second paragraph, consider stating “discovered” rather than “proved to exist” for conciseness.
2.The intro to the third paragraph seems to be a little wordy and a short sentence. Maybe consider rewording it to “Muography operates based on the physical properties of muons as they pass through matter.”
3. In the introduction, you mention other techniques are not as efficient because they do not provide the data needed in time for a safe evacuation. Is there a statistic on how much faster muography works compared to the alternative? This would help emphasize why the future is headed towards muography.
Overall, this was a great read! It was a very creative and interesting blog post, and I look forward to reading your final copy.
Vritti Vashi
Hello Vritti,
I have reworded the sentence in the third paragraph as you suggested and added a statistic about the increased effectiveness of muography. I did not change “proved to exist” to “discovered” in my second paragraph as the muon was actually discovered before 1937, and their existence was simply proved at this time.
Thank you for your feedback!
Paige
Hi Paige,
Very well done on this post. This sort of an analysis of a complex topic such as muography is very impressive and I love the links between nuclear physics and Earth sciences. Here are a few suggestions.
– In Figure 1, I find it a bit strange that in the legend, electrons are denoted e^+ while positrons are denoted e^-; I would have figured that they would be reversed. If possible, I would edit the figure to make the naming convention more clear.
– Near the end of paragraph 2, you say prion and I think you mean pion
– Consider italicizing your figure captions
Again, great work and happy editing.
Cheers,
Joey
Hi Joey,
I have edited Figure 1 as I believe you were correct in suggesting there was an error in it. I have also corrected “prion” to “pion” and italicized my figure captions.
Thank you for your suggestions,
Paige
Hi Paige,
This was a very interesting post, I just have a few suggestions that you may want to consider!
– This is picky in terms of formatting, but I think there are some extra spaces in your reference list.
– Consider modifying your figure captions to differentiate them from the normal text (smaller font, italics etc.)
– In the fourth paragraph when the study is mentioned, it may be helpful to go into more detail about it (if word count permits) or provide the images that led to those conclusions.
Overall this was a great post, good luck with the editing process!
Serena
Hello Serena,
I have fixed the spaces in my citations and italicized my figure captions. In addition, I added an image to expand upon the section you mentioned.
Thanks for your feedback,
Paige
Hi Paige,
Amazing blog post about muons and their relation to volcanoes, I didn’t know how cool they were! I do have a few suggestions to improve your work:
– The second sentence in your first paragraph is a little awkward to read. Try to rewrite it for better flow, such as by saying “Canada primarily has volcanic areas in British Columbia and Yukon, but is also exposed to volcanoes along the United States border that may erupt again in the future (Government of Canada, 2020)”
– Figure 2 is a solid figure in explaining the set up but I feel like you could further expand about some aspects of the recording in the figure caption such as the importance of the hidden chamber and what kind of detectors are used
– You start your second paragraph off with “So what is a muon, and how does this technology work?”. While the blog posts are not as formal as other work, I feel like this disrupts the flow of your post, so it might be better to remove this question
Other than that, it was a great read and I’m looking forward to reading the final product!
– Yash
Hi Yash,
As you suggested, I have reworded the sentence in my first paragraph, added more detail to my Figure 2 caption, and removed the first sentence in the second paragraph.
Thank you for your suggestions,
Paige
Hey Paige,
I really like this blog post, as it’s on a topic that I’ve never heard anything about before, and it’s really well-written! It’s also super interdisciplinary! I just have a few suggestions:
1. In your second paragraph, you have written “muons’”, but I don’t think you need to have the apostrophe at the end. The apostrophe would only be necessary if you were saying, for example, “the muons’ size” or something where normally you would have an “‘s” at the end.
2. In the same sentence I discussed in the above point, you say that muons were “proved to exist” and I think it should be “proven to exist” instead.
3. In the sentence “Muons are formed at great heights in the atmosphere, where cosmic rays, mainly composed of protons, enter the atmosphere…” I would remove the first comma to make it flow better: “Muons are formed at great heights in the atmosphere where cosmic rays, mainly composed of protons, enter the atmosphere…”
Overall, this is a really awesome post! Happy editing,
Lily
Hey Lily,
I have taken out the apostrophe at the end of “muons” and changed the phrase “proved to exist” to “proven to exist”. I have also removed the comma in the second paragraph, as you suggested.
Thank you for your feedback!
Paige