It’s been an interesting week, geoscientifically speaking, and my Twitter feed, from which I harvest interesting snippets about new and significant research, has been buzzing a little more than usual. But the week of 13-19 September, 2018 certainly provided one major Earth science headline — Hurricane Florence — as well as some interesting information on volcanic input into the earth system.
Yes, you did read that right, and yes, of course I’m being tongue-in-cheek. Florence was a slow-moving and deadly hurricane, but one that allows us the opportunity to look at a link between the atmosphere and the Earth.
There’s a wonderful online resource called IRIS (acronym for Incorporated Research Institutions for Seismology) which I would strongly recommend for anyone with an interest in seismicity. One of its features is a live earthquake monitor, which allows you to click on seismic stations worldwide and see real-time data. You can use it to see how a recent earthquake appeared on the seismograph, or you can use it to see what’s happened recently.
The most fascinating thing I’ve seen online this week was how the seismometers in the eastern US recorded the approach of Hurricane Florence. The graphic is a screenshot I took of the recording from Bolivia, North Carolina on 13 September as Florence was making its approach. You can clearly see how the seismic noise increases as the winds intensify.
The reason for this is neatly and concisely explained on the IRIS twitter feed: “the strong winds create ocean waves & pressure fluctuations that cause up/down movements in the water column. These waves hit the seafloor & vibrate the earth. These vibrations are what we detect.”
You can do a lot more with the IRIS earthquake monitor, and the IRIS website itself is full of fascinating data and research updates. I’d strongly recommend it to anyone with an interest.
Katla and Volcanic CO2
Volcanoes are a link between the Earth’s interior and its atmosphere, and they produce a range of gases including carbon dioxide, oxygen, nitrogen, water vapour and sulphur dioxide. Most of these appear as trace amounts only, and the two main ones are carbon dioxide, which contributes to atmospheric warming, and sulphur dioxide, which can contribute to atmospheric cooling.
Exactly how much of each of these gases is produced annually is unclear, and that’s why a new report into Iceland’s Katla volcano may prove to be very significant indeed for our understanding of volcanic contributions to the atmosphere. “…estimates of the total global amount of CO2 that volcanoes emit are based on only a small number of active volcanoes” the report notes, before going on to assess the measured contribution of Katla to the atmosphere.
Katla is a subglacial volcano, and that’s one of the reasons why measuring its output is so difficult. (The same applies to the planet’s many submarine volcanoes.) The research team employed hi-tech measuring techniques and atmospheric modelling to provide an estimate of Katla’s CO2 output — and the results are alarming.
The researchers found that Katla produces around an order of magnitude more CO2 than previously thought. The implications of this are significant, because they suggest that we may need to look again at how atmospheric carbon dioxide is sourced.
The Mineral Cup: Update
Someone asked, in the wake of my reporting of the Mineral Cup, whether I would consider a piece on volcanic minerals. Well, maybe. Strictly speaking there aren’t really volcanic minerals but volcanic rocks, with different types of rock being characterised by the presence of different minerals. It’s certainly a subject I will return to at some stage.
The first round of the mineral cup is all but over, with just one tie left to be decided (and if last year’s runner up, zircon, doesn’t go through I shall probably have to eat my hat). I’ve included the lineup for information, but I want to talk about a couple of the losers.
The first is opal. I was a bit dubious about ice being included as a mineral, and so I am talking about opal. If you remember we talked about what makes a mineral and opal fails in one of those tests: it doesn’t have a crystalline structure. It’s basically a hydrated silicate i.e. made up of water and silica and it probably shouldn’t have been included.
I voted for it, though, and I voted for it because it’s beautiful. (Yes, I’m shallow like that.) It’s also the reason I had a very tough choice between two other minerals, the gorgeous chalcopyrite (a copper-iron mineral) and the even more gorgeous mercury ore, cinnabar. I chose cinnabar but lost, so we’ll hear more about chalcopyrite in the future.
The mineral cup has certainly made me think about minerals and how we use them — from the diamonds, opals and garnets that we wear for their beauty, to the workhorse minerals such as apatite (key to very early life); gypsum (used in plaster); and halite (which you and I know as salt).
Kilauea may have all but stopped (though officially the eruption is ongoing) but the Smithsonian Institution’s Global Volcanism Program reported three new eruptions this week. These were at Veniaminof, in Alaska, and two rather better-known volcanoes, Etna in Italy and the notorious Krakatau in Indonesia.
These going the total of current eruptions around the world to 41, with the figures for the year to date standing at 63, of which 21 began in 2018.