[Oberon]

Originally Posted by kranz

I know that we lack details of the trial, but: are you saying that this Committee, and its members, knowing that there is only a 50% chance to foretell (I deliberately used this word, I hope it has this mystic connotation)whether an earthquake is like or unlikely, claimed that the earthquake is unlikely and people should "relax"?
For me, 50% is not much, so to say. I mean, with a 50% chance of trembles causing an earthquake we wouldn't need "top experts" to do that, right?

The trouble is, Kranz, if they were to say anything other than it is unlikely then it would cause people to leave the area, and they were likely under a lot of pressure to be 'absolutely 100% sure' before saying that there WOULD be an earthquake because of the cost of lost revenue of people leaving the area, and lost taxes.
50% is pretty much spot on, it either would happen, or it would not happen. You simply cannot be any more accurate than that. Seismologists have been predicting an earthquake that will devastate the San Francisco area for the last twenty to thirty years, they call it 'The Big One' on the San Andreas fault, but they can't tell you when it will happen, it could happen tomorrow, it could happen in a hundred years time. Like I said in my previous post, even the Japanese, who have the best earthquake monitoring system in the world can only give a minutes warning of an earthquake, maximum, often it's less.

Any examples?

Sure.

http://www.nature.com/nature/journal.../392743a0.html

http://books.google.co.uk/books?id=n...=0CB0Q6AEwADgU

In 1976 Dr. Brian Brady, a physicist then at the U.S. Bureau of Mines, where he had studied how rocks fracture, "concluded a series of four articles on the theory of earthquakes with the deduction that strain building in the subduction zone [off-shore of Peru] might result in an earthquake of large magnitude within a period of seven to fourteen years from mid November 1974." In an internal memo written in June 1978 he narrowed the time window to "October to November, 1981", with a main shock in the range of 9.2±0.2. In a 1980 memo he was reported as specifying "mid-September 1980". This was discussed at a scientific seminar in San Juan, Argentina, in October 1980, where Brady's colleague, Dr. W. Spence, presented a paper. Brady and Spence then met with government officials from the U.S. and Peru on 29 October, and "forecast a series of large magnitude earthquakes in the second half of 1981." This prediction became widely known in Peru, following what the U.S. embassy described as "sensational first page headlines carried in most Lima dailies" on January 26, 1981.
On 27 January 1981, after reviewing the Brady-Spence prediction, the U.S. National Earthquake Prediction Evaluation Council (NEPEC) announced it was "unconvinced of the scientific validity" of the prediction, and had been "shown nothing in the observed seismicity data, or in the theory insofar as presented, that lends substance to the predicted times, locations, and magnitudes of the earthquakes." It went on to say that while there was a probability of major earthquakes at the predicted times, that probability was low, and recommend that "the prediction not be given serious consideration."
Unfazed, Brady subsequently revised his forecast, stating there would be at least three earthquakes on or about July 6, August 18 and September 24, 1981, leading one USGS official to complain: "If he is allowed to continue to play this game ... he will eventually get a hit and his theories will be considered valid by many."
On June 28 (the date most widely taken as the date of the first predicted earthquake), it was reported that: "the population of Lima passed a quiet Sunday".The headline on one Peruvian newspaper: "NO PASO NADA" ("Nothing happens").
In July Brady formally withdrew his prediction on the grounds that prerequisite seismic activity had not occurred. Economic losses due to reduced tourism during this episode has been roughly estimated at one hundred million dollars (emphasis mine)

http://www.telegraph.co.uk/news/worl...lse-alarm.html

It is a case of the boy who cried wolf, I'm sure you've heard of that particular fable, if you take every single minor earthquake as being the foreshock of a major earthquake then eventually no-one will listen to you, which will cause problems if and when it does actually happen.
After all, only five to ten percent of all small earthquakes turn out to be foreshocks of a major earthquake, so even a cluster of small earthquakes in an area is not a reliable fore-warning of a major event.

if they were members of an official committee, that is a poor excuse tbh. They should have done their job above all the (alleged) pressure. If they failed to that pressure, that's their fault.

If you were in their shoes, without the benefit of hindsight, knowing that you could lose your job for a 5-10% chance of being right, would you gamble it? Would you want to be tarred as the 'Chicken Little' constantly warning after every small earthquake that the sky was about to fall in?
Honestly I don't know what kind of pressure they were under, I don't know how the Italian seismologist system interacts with the government. However it is likely that the seismologists are paid by the government, and thus if they issue a series of false alarms which cause financial problems for the government, and thus show themselves as unreliable, then they would likely have their funding cut. That is subjective though, as you said about the data from the trial itself, there's not enough data to be sure.

does it mean that people should take completely no responsibility for their decisions while dealing with seismology?

I think that seismologists should stop being asked if an earthquake is going to happen, because all they can do is highlight an area that has a likely risk, they can give a time-line but even then it's subjective. Honestly you might as well also turn around and blame the people who died for living in an area which has earthquakes in it. Does this mean that people who get killed by earthquakes should take responsibility for living in an area which have earthquakes in it?