Science: Forecast: Future Shock

The notice was posted on the wall outside offices of the U.S. Geological Survey on Dec. 30, 1976. Issued by six USGS scientists, it predicted that an earthquake measuring 3.5 on the Richter scale would occur within a 15 kilometer (9.3 mile) radius of a ranch near Hollister, Calif., during January 1977. On Jan. 6, a quake measuring 3.2 shook the ground about 10 kilometers (6.2 miles) from Hollister. This successful, unpublicized prediction shows that scientists are moving closer to their goal of reliable earthquake forecasts (TIME cover, Sept. 1, 1975). But predicting how people will react to public forecasts is still somewhat of an inexact science.

In an effort to discover what reaction there would be following the forecast of a major earthquake, J. Eugene Haas and Dennis S. Mileti of the University of Colorado’s Institute of Behavioral Science interviewed hundreds of public officials, businessmen, journalists and families in earthquake-prone areas of California. Their conclusion, made public in a 40-page study: unless planning is begun now to prevent it, “the first credible earthquake prediction … will exact a very high price in economic dislocation and social disruption.”

In their study, Haas and Mileti develop the following four-phase scenario based on their interviews and advances in earthquake forecasting:

> Phase One. Experts announce in July 1977 that there is a 25% probability that a damaging quake will occur within three years in a specified urban area. About a fifth of the affected homeowners try to buy earthquake insurance for the first time.

> Phase Two. Refining their data, experts predict in August 1978 that there is a 50% probability of a 7 or greater quake occurring in the fall of 1980. New earthquake insurance policies become unavailable in the “target” area. Construction projects are held up and unemployment in the building trades approaches 80%. People cut back on spending and put more money into savings accounts. Many consider moving out of the area; by the fall, 8% have done so.

> Phase Three. In November 1979 scientists cite an 80% probability of a 7.1 to 7.4 quake during September 1980. People begin stockpiling food and medical supplies, and officials plan to lower the water level behind dams. About half of the remaining residents make plans to leave, and both retail sales and real estate values drop precipitously, while unemployment climbs.

> Phase Four. In July 1980 the quake is pinpointed to occur during the first week of September. By the end of August, some 60% of the area residents have left, 10% permanently. Of those remaining, many have begun eating and sleeping outdoors and avoiding older, taller buildings; school openings are postponed. A week before the quake is due, Government agencies move to trailers and other temporary facilities, well away from buildings and power lines.

Haas and Mileti acknowledge that these preparations will have tremendous social costs. But the benefits in lives saved will be far greater. Despite their early-warning system, Chinese scientists missed the signs that heralded last summer’s 8.2 magnitude quake in Hopeh Province. No prediction was issued, the quake caught large numbers of the population inside houses and other buildings, and 655,000 people were killed.