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March 6, 2001

So-called earthquake ‘predictions’ only scare people, UW scientists say

News and Information

The Puget Sound region is being plagued by rumors that another major earthquake is imminent, but University of Washington scientists say the rumors are being fueled by people who have no scientific basis for their far-fetched claims.

“There is no scientifically reliable way of predicting the precise timing or intensity of an earthquake,” said Ruth Ludwin, a research scientist in the UW’s department of Earth and Space Sciences.

The UW seismology laboratory has received numerous telephone calls in the last two days from parents and teachers concerned that children have been frightened by rumors that a large earthquake will happen this week. The rumors, said Bill Steele, the lab’s coordinator, apparently have come from people claiming to be able to predict that another earthquake will hit the Puget Sound region in the wake of last week’s magnitude 6.8 Nisqually earthquake.

Typically, such predictions are so vague and have such large parameters that virtually any ground shaking would fulfill the forecast. In addition, those who claim success in forecasting quakes seldom acknowledge when their predictions are wrong, which is the vast majority of the time, said Steve Malone, a UW research professor of Earth and space sciences.

“The odds of a big earthquake are no different – not greater or less – than they were two weeks ago, before this earthquake hit,” Malone said. “This earthquake did not change the odds.”

Because of the historic and geologic record, seismologists know generally where and how often earthquakes occur. For instances, in 1949 and again in 1965 the Puget Sound region was shaken by quakes similar to the one last week.

But there is no way to pinpoint a precise day or even a year when a large quake will happen, Ludwin said. That is because geologic time occurs on scales so much larger than what humans experience. So trying to forecast precisely when a large earthquake will strike a particular area is like trying to predict down to the tenth-of-a-second when it will start to rain in that same area.

“On a geologic time scale, the separation between the 1949 earthquake and the 2001 earthquake is infinitely small. They’re like bang-bang,” she said. “We don’t expect damaging aftershocks from this earthquake. So we think people should be thinking long-term instead of short-term, because long-term human time is short-term geologic time.”

Details of the history of failure in earthquake prediction is on the Internet at http://www.geophys.washington.edu/SEIS/PNSN/INFO_GENERAL/eq_prediction.html

“Earthquake prediction is a popular pastime for psychics and pseudo-scientists, and extravagant claims of past success are common. Predictions claimed as ‘successes’ may rely on a restatement of well-understood long-term geologic earthquake hazards, or be so broad and vague that they are fulfilled by typical background seismic activity,” according to the Web site. “Neither tidal forces nor unusual animal behavior have been useful for predicting earthquakes. If an unscientific prediction is made, scientists cannot state that the predicted earthquake will not occur, because an event could possibly occur by chance on the predicted date, though there is no reason to think that the predicted date is more likely than any other day.

“Scientific earthquake predictions should state where, when, how big, and how probable the predicted event is, and why the prediction is made. The National Earthquake Prediction Evaluation Council reviews such predictions, but no generally useful method of predicting earthquakes has yet been found.”

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For more information, contact Ludwin at (206) 543-4292 or (206) 685-8180; Malone at (206) 685-3811 or steve@geophys.washington.edu; or Steele at (206) 685-8180.