Persinger’s Tectonic Strain Theory: Strengths and Weaknesses

Claude Maugé
Magonia 24, November 1986

Sightings of lights in the sky are often neglected by many ufologists who consider them too ‘simple’, and unworthy of their avant-garde researches. Yet this simplicity is an important factor. Abnormal luminous phenomena can be compared with rather well-known manifestations, such as St Eilmo’s Fire, auroral phenomena or optical refraction phenomena, many examples of which can be found in Corliss’s books.
Others, such as ball lightning, are progressively integrated into the scientific corpus, or are phenomena claimed by ufologists, but studied by scientists (e.g. green fireballs).

Several authors today think that UFOs, or at least a large part of them, are geophysical phenomena essentially linked with seismicity. The best known ones are Michael Persinger in Canada, and Paul Devereux in Great Britain. I would like to take a particular look at Persinger’s Tectonic Strain Theory (TST), which is indisputably one of the most important and interesting attempts at a study of the UFO phenomenon.

Tectonic Strain Theory

There is no question of expounding this theory in full here. It is complex, still evolving, and is the subject of numerous papers. Its outlines are presented, for instance, by Persinger [8, 10], Wanderer [21] or Maugé [5]. Its essential bases are very well summarised by Persinger himself [1O] in the following passage:”This theory requires the analysis of the UFO problem at three separate levels: 1, the large scale space-time pattern; 2, the particular UFO event, and 3, the neuropsychological contributions of the observer [...] Each component is characterised by a major hypothesis. First, most UFO phenomena are generated by processes associated with crustal deformation (or ‘earthstress’) over geophysical time. Second, the single UFO event is a highly localised (a few metres), transient (a few minutes), extraordinarily energetic electromagnetic-like manifestation of this earth stress. Third, the rich variety but persistent common themes of close UFO encounters are a predictable consequence of the direct effects of the UFO event upon the electrochemical activities of the observer’s brain.”However, TST presents a certain number of ambiguities and weak points, some of which are seriously damaging to the model. Rutkowski [19,20] has already presented some objections, insisting on the question of the selection of ufological data, statistical problems, and the weakness of the geophysical basis of the model.

Reliability of ufological data

The first point is fundamental, and Rukowski is unfortunately totally right. None of the data sources used to build TST (Fort, UFOCAT, Fate) seems to be reliable enough to be the basis for a valid study. Persinger [17] reproaches Rutowski for having criticised his sources using value judgement and not empirical criteria. However, it was Hendry’s empirical experience which had led him to reject UFOCAT as a reliable statistical tool.[3]

As for me, I showed [4] albeit with a very limited and particular sample, that the 29 trace cases of the French 1954 wave and the 16 Belgian trace cases which appear in a computer printout from UFOCAT [6] give the following results (the first number corresponds to the French cases, the second to the Belgian ones):
  • sound cases (unexplained after serious counter enquiry), 1/1;
  • inconclusive cases (lack of sufficient data, unreliability of primary sources, etc.), 8/6;
  • dubious cases (with particular reasons for caution), 7/1;
  • explained cases, 13/8.
Yet these ‘physical evidence’ cases are often regarded as the most reliable records by researchers.

Persinger recognises that there are misinterpretations which have nothing to do with TST, but he is apparently not well informed of the primary ufological literature, for which one cannot blame him. So he is wrong when he thinks that in UFOCAT the UFO types with medium to high strangeness (types 3 to 9) “did not include non-UFO reports” [18], and even that the ‘luminosities’ reports (types 3 to 6) form “a very select sub-cluster”. How it is proved in several high-strangeness cases, and probable (or at least possible) in the large majority of them, that they correspond to misinterpretations rather more sophisticated than in the cases of reports of stationary of regular-trajectory luminosities (UFOCAT types 1 and 2). Rutkowski [2O] uses the same argument, and notes that:

“Persinger dismisses this argument by saying that using a consistent data-base will allow the relationship to come through anyway, subtracted out as ‘noise’ in the final analysis. However a 90% level of noise is not that easy to filter out, especially if one cannot distinguish it from the rest of the data.” (I think that the 10% ‘unknowns’ residue generously conceded by Rutkowski is greatly overestimated.)

The Correlation Problem

But if the data are inadequate, why do the various calculations converge on rather coherent and quite impressive results? Several arguments allow us to think it might be statistical artifacts, which Persinger recognised as possible for the first results concerning the Washington-Oregon area.[18]

Persinger in fact tests several functions in varying the co-efficients of the geophysical variables, and he keeps the one(s) which give the best correlations. This procedure is mathematically accurate, but the seismic-geomagnetic variables are not always independent, which can bias statistical calculations, and the little reliable UFO data are heterogeneous, which can introduce other biases. The fact that optimal analysis increments, selected functions, reached correlations are different according to the region studied is indeed partly justifiable by different geology; but it can also reveal artifacts, as long as we do not have causal or at least partly quantified reasons for the variations (conversely, such causal and quantified reasons would be very strong arguments in favour of TST).

It is clear the seismic is used as an observable indicator of the tectonic strain: earthquakes do not directly produce UFOs, the cause of both phenomena is the unobservable strain. However, like Rutkowski [19], I thought that too great a distance between luminous events and corresponding seisms is “intuitively unsatisfying”. Persinger [17] partly replies to this objection: “The requirement of such large space-time frames within which to see a phenomenon is not unique to [his] hypotheis” and that the argument “would repudiate the most recent developments for the forecasting of earthquakes” which use parameters changing months before ‘quakes. This is however an argument by analogy, and the matter is to know if it is valid for our problem, because the variables mentioned are not those uses in TST.

Some of the correlations obtained by Persinger are not so well founded as the author claims. For instance, his results for five European countries, France and Italy included [11], absolutely do not predict (a posteriori) the major French-Italian wave in autumn 1954. It is however possible that the used function predicts this peak with a short delay, since the results show a very high score for 1955, but Persinger does not note this discrepancy. In any case, the predicted continuous peak from 1955 to 1959 is erroneous: the year 1957 only showed an ‘actual’ peak, much lower than the 1954 one.

The predicted peaks in 1946, 1963 and 1964 seem likewise to have been non-existent in these countries. The 1954 wave is also not predicted in an improved version [16], which is also unable to predict the 1973-1974 wave. In both versions the function used was built with Fort’s data during the 1870-1905 (or 1910) interval.

But were the numbers of European events reported by Fort significant of the actual numbers, or of the numbers of events reported by witnesses? This problem is always a potential bias in all ufological statistics.

It may be logical that the 1954 wave, which was of a sociological nature to a very large extent, is not predicted by geophysical variables. But if so, why are these variables able to predict the major 1897 U.S, wave, which was also essentially journalistic? 22] Here is another weakness of TST, which totally neglects sociological factors, yet these are fundamental in ufology. Persinger admitted their role [9] but the only aspect he considers is the variation of imagery according to culture. In his reply to Rutkowski he even mentioned the hypothesis that “much non-seismic UFORs [UFO reports] were randomly distributed within each [space-time] increment”. We know already how important is the role of the media in the production or the extension of several UFO waves. Such sociological factors also explain the correlations between numbers of UFO reports in UFOCAT and Fate, and these correlations therefore tell us nothing about the reliability of data, contrary to what Persinger claims. [17]

Finally, some methodological details seem to me to be unclear; I shall cite only one. Persinger notes (e.g. 18) that he seeks to “attenuate the effects from outliers”. This is mathematically accurate in a ‘normal’ data set, outliers are often aberrant points. But in ufology it is possible that such a procedure eliminates the right data – that is, strange and reliable cases differing from the ufological ‘norm’, whereas the ‘norm’ would correspond to badly investigated and potentially explainable cases.

Persinger’s statistical results therefore pose some serious problems of interpretation. It would be desirable to examine the statistics much more exhaustively than I have been able to, for instance in comparing carefully the predicted peaks with the actual ‘waves’ It would be helpful if an expert in statistical theory could say if it is possible that so many apparent converging results can render only statistical artifacts. Such questions are not unwarranted, because Persinger writes that “the critical test of the hypothesis is the systematic spatial and temporal coupling between UFORs and earthquake measures within a region” [17] – that is, the obtained correlations.

The Individual UFO Event

We have for the time being no viable physical model to explain the formation of the ‘electromagnetic column’ (EM column). But this situation is not damning, particularly for ufologists who speculate far beyond the most ‘advanced’ physics. Persinger [17] disputes Rutkowski’s argument [19] according to which “the geophysical basis for the theory [...] is extremely dependent upon recent reports of luminous effects produced by strain on rock during fracture tests”. In fact, several authors, such as Brady and Rowell [1] or Devereux et al [2] report having obtained a light emission in such circumstances. Others, such as Ogawa et al [7] notice the emission of (low frequency) EM waves. The important question is the problem of the extrapolation from laboratory ‘micro’ results to the natural scale, especially since, as far as I know, all Persinger’s interpretations are purely qualitative.

Effects on Witness’s Central Nervous Systems

The model assumes that in close encounters the electromagnetic field of the EM column can induce several types of physiological effects: it can produce induced currents in various structures of the central nervous system, particularly those of the temporal lobe. A consequence could be very complex and vivid hallucinations. But such hallucinations are obtained with direct stimulus by intracranial electrodes, in surgical circumstances, amongst essentially epileptic patients. I have not read all of Persinger’s references, but those I have do not mention these phenomena for subjects placed in EM fields. Hallucinations are the crude (e.g. phosphenes), and the associated physiological phenomena are of the headache, fatigue or pain type. We are again faced with the problem of extrapolation: is it legitimate or is it not?

But it is perhaps Persinger himself who brings out one of the most interesting arguments against the TST, or rather against the large number of UFO sightings it is supposed to explain. First, he rightly notes the basic identity between UFO ‘sightings’ and religious entity ‘sightings’. [10] Second, he considers that “many close-encounter-type experiences (concerning gods, demons or aliens) could be produced by temporal lobe dysfunctions not initiated by close proximity to UFO-related luminosities” [10, 12] but by various stimuli such as fatigue, social isolation, perturbations of circadian rhythms, hypoxia, personal crisis, certain drugs, and so on. Third, he is developing the temporal lobe transients hypothesis, endogenous or exogenous with ‘mundane’ stimuli, to explain religio-mystical and paranormal experiences. [13, 14, 15] One can then wonder whether an original geophysical process of large extent is needed to trigger off the mechanism of the ‘UFO’ sighting.In his reply to Rutkowski, Persinger says a “substantial portion” of UFOs generated by tectonic strain “would not be evoked by the traumatic stimulation” that is the direct action on the brain. If this “substantial portion” contains a substantial number of close encounters, this statement is new and it dims the impact of the above criticism, but I fear the “substantial portion” concerns only distant sightings, therefore the objections still have their value.


In fact, TST seems to be unnecessary for the large majority of sightings which, besides inevitable hoaxes and psychopathological cases, would be the concern of the ‘socio-psychological hypothesis’. These cases would be ‘only’ more or less mundane misinterpretations, sometimes complex, either with an objective description, or on which the witness grafts a set of themes and images according to what he knows, more or less consciously, about the UFO phenomenon.

As for the remainder, possible temporal lobe transients or similar processes and original geophysical phenomena, some of which would be the concern of a TST limited to particular areas and/or types of sightings, seem for the time being well sufficient.But if Persinger could succeed firstly in reinforcing the value of his correlations (particularly by taking sociological factors into account); secondly in clarifying the processes which create the ‘EM Column’, and thirdly in clarifying the processes of the action of this ‘column’ on the central nervous system, then TST will really deserve the label of the best scientific theory of UFOs.

  1. BRADY, B,T, and ROWELL, G. A, ‘Laboratory investigations of the electrodynamics of rock fracture’ Nature, 29 May 86, 321, no. 6069: 488-492.
  2. DEVEREUX, P,, McCARTNEY, P, and ROBINS, D, ‘Bringing UFOs down to earth’, New Scientist, 1 Sep, 83, 99, no. 1373; 627-630.
  3. HENDRY, A, The UFO Handbook, Doubleday, 1979: 244-247.
  4. MAUGÉ, C, ‘OVNI-OVI; sur un certain état de la question’, Inforespace, June 83, n’63; 6-8
  5. MAUGÉ, C, ‘Introduction a la théorie des contraintes tectoniques de M. Persinger’, Inforespace, Dec, 85, n°69;15-26.
  6. MERRIT, F, Physical Traces of UFO sightings – a computer printout, CUFOS, 2nd ed, 1980.
  7. OGAWA, T, OIKE, K, and MIURA, T, ‘Electromagnetic radiation from rocks’, Journal of Geophysical Research, 30 June 85, 90, no.D4; 6245-6249.
  8. PERSINGER, M. A. ‘Possible infrequent geophysical sources of close UFO encounters; expected physical and behavioural-biological effects’, in HAINES, R. F., (Ed) UFO Phenomena and the Behavioural Scientist, Scarecrow Press, 1979: 396-433.
  9. PERSIN6ER, M. A., ‘Earthquake activity and antecedent UFO report numbers’, Perceptual and Motor Skills, 1980, 50, no.3, part l; 791-797.
  10. PERSINGER, M. A., ‘Predicting UFO events and experiences’, 1982 MUFON UFO Symposium Proeedings, MUFON, 1982; 33-40.
  11. PERSINGER, M. A., ‘Geophysical variables and behaviour: VII, Prediction of recent European UFO report years by nineteenth century luminosity and solar-seismic measures’, Percept, Motor Skills, 1983,56, no.l; 91-95
  12. PERSINGER, M. A., ‘Geophysical variables and behaviour: IX, Expected clinical consequences of close proximity to UFO-related luminosities’ op. cit,; 259-265.
  13. PERSINGER, M. A., ‘Religious and mystical experiences as artifacts of temporal lobe function: a general hypothesis’. Percept, Motor Skills, 1983, 57,no.3 part 2: 1255-1262.
  14. PERSINGER, M. A., ‘People who report religious experiences may also display enhanced temporal lobe signs’, Percept, Motor Skills, 1984,55, no.3; 963-975
  15. PERSINGER, M. A „ ‘Propensity to report paranormal experiences is correlated with temporallobe signs’, Percept. Motor Skills, 1984,59,n’2; 583-586.
  16. PERSINGER, M. A., ‘Prediction of historical and contemporary luminosity (UFO) reports by seismic variables within Western Europe’, Experientia, 1984,40; 676-681.
  17. PERSINGER, M. R., ‘Geophysical variables and behavior: XXVI, A response to Rutkowski’s critique of the tectonic strain hypothesis for UFO phenomena’, Percept. Motor Skills, 1985, 60, no.2; 575-582.
  18. PERSINGER, M. R. and DERR, J. S., ‘Geophysical variables and human behaviour: XIX, Strong temporal relationships between inclusive seismic measures and UFO reports in Washington state’, Percept. Motor Skills, 1984, 59, no.2; 551-566.
  19. RUTKOVSKI, C. A., ‘Geophysical variables and human behaviour: XVI, Some criticisms’, Percept. Motor Skills, 1984,58, no.3; 840-842, Reprinted in following reference:
  20. RUTKOVSKI, C. A., ‘UFOs on the rocks’, CUFOS Associate Newsletter, Dec. 1984/Jan. 1985; 4-6
  21. WANDERER, R., 'The Persinger theory' MUFON UFO Journal, June 1984, no.184; 9-1l; Westrum, R., Communication at the Rencontre Ufologique du Bugue, France, summer 1981.