PREDICTING EARTHQUAKES

August 18, 2004
		In recent years, scientists have been moving ever closer to one day being able to predict when and where a major earthquake could occur. A leading scientist in earthquake prediction answers your questions about the latest developments in the field.

Online NewsHour Special Report: Predicting Earthquakes Forum Introduction What is the difference between a "return interval" and a "recurrence interval"? Seismologists study earthquakes, but who studies how to mobilize society for disaster? Why is it that the New Madrid Fault is very rarely mentioned in quake discussions? If people could turn on their TVs to find out an earthquake was coming, wouldn't there be widespread panic? Are we going to have a 19-year quake cycle here in California? What are the chances of a major earthquake through the mid-U.S.A., where none has occurred since the early 1800s?	Bob Macartney of Mountain View, Calif., asks: If, as Dr. Zoback suggested, I could turn on my TV to find that there was say an 80 percent chance of a 6.0 or larger quake in the next two weeks, what are the social implications? I suspect there would be panic, people would quickly leave the area, food and medicine would be hoarded, and the fabric of society would be greatly stressed. Would any predictions short of ones better than we now have, even for hurricanes, not cause more damage than they might prevent? Of course we know there will be large earthquakes and preparing, especially making buildings stronger, makes sense. Dr. William Ellsworth responds: Social scientists who have studied the reactions of the public to predictions and warnings have found that the public does not panic. Instead, they take a measured response to credible information. The challenge for Earth scientists and emergency management officials will be to make sure that information is being reported correctly and is widely available. Assessing the cost of predictions is a difficult proposition, as it is very difficult to measure using standard scientific methods. However, the cost of extreme events is enormous -- $40 billion in losses from the 1994 Northridge earthquake and over $500 billion dollars in direct and indirect losses in the 1995 Kobe, Japan earthquake. So the stakes are very high. As you correctly surmise, preparation is the key.