I have a habit of downloading and reading random earth science articles with catchy titles. Sometimes I stumble on ideas that are allegedly prevalent in some branch of earth science, but about which I knew nothing. I recently had this experience when looking through the latest issue of Tectonophysics. The article I am talking about is by S.A. Pulinets and M.A. Dunajecka from Ciudad Universitaria in Mexico. As a disclaimed I will state now that I am neither an earthquake expert or an atmospheric chemist, so I would be interested in hearing the opinions of specialists in either of those fields. I'd hate to inadvertently promote pseudoscience. The full reference is
Pulinets, S.A. and Dunajecka, M.A. (2007) Specific variations of air temperature and relative humidity around the time of [the] Michoacan earthquake M8.1 Sept. 19, 1985 as a possible indicator of interaction between tectonic plates, Tectonophysics, v. 431, p. 221-230.
It has been known for a while that radon levels in the atmosphere can correspond to tectonic activity. Direct measurements of radon levels have shown large fluctuations immediately preceding earthquakes. What this paper presents is the idea that instead of a direct measurement of radon levels, remotely sense temperature and humidity measurements can be used as a proxy for the same phenomena. When Radon in the air decays, it ionizes other nearby molecules or atoms. These newly formed ions are then hydrated by atmospheric water, with the result that air humidity drops. The latent heat of evaporation is released from the water during the phase transformation, which results in a temperature increase. So, big pulses of Radon into the atmosphere, as are associated with tectonic activity and seem to occur leading up to earthquakes, results in an initial decrease in humidity and increase in temperature. The radon flux reaches a maximum and starts to decrease just prior to the "seismic shock", during which time there is a corresponding rise in humidity and drop in temperature.
Truth is I do not feel like that good of a filter for climate data, because from my perspective, the data presented in this paper do not seem as tell-tale as the authors imply. There are many swings in temperature and humidity that are not associated with earthquakes. But, I am still intrigued. I have heard the term "earthquake weather" before, which usually makes me chuckle.. But the temperature and humidity swings presented in this paper would definitely be noticeable. Anyways, I'd love input from anyone who knows more about this, I learned long ago not to trust everything that is published (as a matter of fact, I am counting on that for this paper I am working on, perhaps these authors have been asked one time too many when that paper is going to be done, and they just wanted it out the door). They reference many similar studies, which is reason enough to visit the library.
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10 comments:
I've blogged about similar phenomena before - my take is that although it seems that these phenomena sometimes appear to precede earthquakes, the occurence of similar signals without any ensuing earthquake somewhat limits their usefulness as a diagnostic tool - it's clear that any relationship to tectonic activity is not a simple one.
I agree. The figure they have showing soil radon concentrations, measured independently, is more convincing that just the temp and humidity. Thanks for the link to your post.
I meant to add that as a predictive tool I also agree it seems very far off, if possible at all.
You found that figure convincing? I won't believe it until I see a much longer record - what they've provided is not enough to get a sense of normal seasonal variability.
Got me. I meant relatively more convincing when compared with the figures of temp and humidity, which are very noisy. Still intrigued.
I'm too lazy to actually to calculations on the back of the envelope, but just glancing at the flap from across the room, it seems like the total heat available from Radon << atmospheric specific heat, and radon <<< atmospheric water content.
Also, if this effect is true, there should be a relationship between the magnitude of the effect and the mafic/felsic ratio of the rocks on the fault, since mafics are low in U.
Note that for specific heat of water to be a factor, the water has to stay liquid. If it immediately re-evaporates, then the dQ is zilch. Ditto if you form hydrated ions that re-react back into satble molecules.
I suppose all the math is in his '04 book, but as I said, I'm lazy.
I recently watched a television program about animals and their apparent sensitivity to 'pre-shocks'. The one thing that was missing in the show, however, was what seismometers have actually recorded with reference to these anecdotal stories. That is, even though humans can't feel these, what did our machines feel?
The other thing in the show that I disliked was using words like 'predict' and 'warn' with regards to animals. They aren't actively engaged in prediction (at least not in the way we do)...they are responding/reacting to something. We then have interpret it and use it as a warning.
If odd behavior in animals predicted earthquakes anyone who owned a rabbit and/or kitten would expect them every day.
I'm just Sergey Pulinets, one of authors of the paper.
The problem is that due to some discussion between seismologists they decided that radon is not a precursor and regular observations of radon were stopped in many countries (like after decree of Communist party). I have at least one direct one-to-one correlation between radon and humidity at Acapulco before Copala M7.4 earthquake in September 1995.
I accept the critics that data are not very convincing, but the aim of paper was to conmemmorate the 20-th annyversary of Michoacan earthquake in 1985, and we used tha very old data in paper format.
I published recently in Eos the short paper explaining not only the thermal but ionospheric anomalies as well.
If anybody wants more references, on can find the electronic versions of publications (including humidity calculations) at my WEB page:
http://tonatiuh.igeofcu.unam.mx/~pulse/online.htm
I'm open for any questions and discussions
Sincerely
Sergey Pulinets
Sergey,
Thank you for the response! I posted about this paper because I had never heard of the technique before, and it really intrigued me. As I say in my blog, I am a thermochronologist by training, so this paper came up in my attempt to broaden my skills. Thanks for the links also, I'll have to check them out.
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