VAN Method - Criticisms of VAN

Criticisms of VAN

The usefulness of the VAN method for prediction of earthquakes has been a matter of debate. Both positive and negative criticism on the VAN method is summarized in the 1996 book "A Critical Review of VAN", edited by Sir James Lighthill. A critical review of the statistical methodology was published by Y. Y. Kagan of UCLA in 1997.

Regarding predictive success - VAN has claimed to have observed at a recording station in Athens a perfect record of a one-to-one correlation between SESs and earthquake of magnitude ≥ 2.9 which occurred 7 hours later in all of Greece. However, it was later shown that the list of earthquake used for the correlation was false. Although VAN stated in their article that the list of earthquakes was that of the Bulletin of the National Observatory of Athens (NOA) it was found that 37% of the earthquakes actually listed in the bulletin, including the largest one, were not in the list used by VAN for issuing their claim. In addition, 40% of the earthquake which VAN claimed had occurred were not in the NOA bulletin. Examining the probability of chance correlation of 22 claims of successful predictions by VAN of M > 4.0 from January 1, 1987 through November 30, 1989 it was found that 74% were false, 9% correlated by chance, and for 14% the correlation was uncertain. No event correlated at a probability greater than 85%, whereas the level required in statistics for accepting a hypothesis test as positive is 99%, sometimes relaxed to 95%.

Regarding mechanism - An analysis of the propagation properties of SESs in the Earth’s crust showed that it is impossible that signals with the amplitude reported by VAN could have been generated by small earthquakes and transmitted over the several hundred kilometers distances from the epicenter to the receiving station. In effect, if the mechanism is based on piezoelectricity or electrical charging of crystal deformations with the signal traveling along faults, then none of the earthquakes which VAN claimed were preceded by SESs generated an SES themselves. There is also some doubt that phenomena of rock physics seen in the laboratory can be assumed to take place in the Earth’s seismogenic crust.

VAN’s publications are further weakened by not addressing the problem of eliminating the many and strong sources of change in the magneto-electric field measured by them, such as telluric currents from weather, and man-made signals, such as neighbors of Varotsos turning on and off their television set in suburban Athens. One critical paper clearly correlates an SES used by the VAN group with digital radio transmissions made from a military base.

Most importantly, the method is hindered by a lack of statistical testing of the validity of their hypothesis, by changing the parameters of the hypothesis constantly (the moving goal post technique).

Finally, one inherent problem of the method is that, in order for any prediction to be useful, it has to predict a forthcoming earthquake with a reasonable accuracy with respect to timeframe, epicenter and magnitude. Otherwise, if the prediction is too vague, no feasible decision (such as to evacuate the population of a certain area for a given period of time) can be made. Errors of location for the VAN technique are presently less than or equal to 100 km.

Major opponents of VAN were the Greek seismologists Vassilis Papazachos and G. Stavrakakis. The debate between Papazachos and the VAN team has repeatedly caused public attention in their home country Greece and has been extensively discussed in the Greek media.