Dismal Prospects for Short-Term Earthquake Prediction
The best way to protect people against the devastating effects of earthquakes is by making buildings earthquake-resistant, geophysicists say. Earthquake forecasts along the lines of hurricane warnings are not just around the corner. There is no known way of predicting exactly when and where an earthquake will happen - and any claims that they can be predicted are not supported by the evidence.
This week, the Royal Astronomical Society publishes a special section in the Geophysical Journal International (GJI) with 13 papers devoted to the subject of earthquake prediction. It follows a conference convened by the RAS exactly a year ago to discuss how the performance of would-be earthquake predictors can be assessed. Attendees also addressed the question of whether it is possible to say in advance exactly when and where earthquakes will strike. They concluded that scientific prediction is probably impossible in any practical sense.
Dr Russ Evans, RAS Vice-President and Editor of the special issue of GJI commented:
'Since the modern science of seismology began about a hundred years ago, most geophysicists have been pessimistic about the possibility of practical earthquake prediction, although their arguments have only amounted to "It's just too complicated". What this meeting and the book of papers has done is to put some flesh on the bones of this argument, spelling out what "too complicated" means.
Some of my colleagues have pointed out that, to be socially useful, predictions need to be both accurate and reliable -- much more accurate and reliable than, say, weather forecasts. But this means that any warning signs would have to be glaringly obvious, and other colleagues have pointed out that they aren't.'
Contributors to GJI show that despite thirty years of extensive efforts to find telltale earthquake precursors throughout Europe, the USA, the former Soviet Union, and Japan, no reliable precursors have been found. Even the best schemes suggested for predicting earthquakes have done little better than guessing at random would have done. Theoretical ideas about the way in which the Earth responds to the stresses within it tend to support the viewpoint that earthquakes are by nature unpredictable.
Dr David Booth, co-organiser of the conference, adds, "This does not mean that society cannot defend itself against earthquakes. Seismologists know where earthquakes are more and less likely, and can advise civil engineers and architects on the likely degree of shaking that their buildings will be subjected to. These building professionals know how to put up structures in such a way that they will survive and protect their occupants. So the way forward in earthquake protection remains as it has been for the last sixty years, to build appropriately in earthquake-prone areas."
The papers in Geophysical Journal International VOL. 131 NO. 3 DECEMBER 1997
SPECIAL SECTION - ASSESSMENT OF SCHEMES FOR EARTHQUAKE PREDICTION