Quake Predictor

Geysers like Old Faithful fire fountains of steaming water from the earth at impressively regular intervals. When the intervals change, though, it may be time to stop being impressed and start running for cover. According to a report in Science, the interval between one geyser's eruptions, at least, tends to fluctuate before a major earthquake takes place. The only catch: the quakes happen far away.

The report is based on a study of a geyser near Calistoga, a town in Northern California's wine country noted for its hot springs. Two scientists, now at Washington's Carnegie Institution, analyzed the timing of eruptions from 1973 to 1991. They found that the schedule was disrupted one to three days before each of the three biggest earthquakes of the period in the region. Just before the devastating Loma Prieta quake that hit the San Francisco area during the 1989 World Series, for example, the time between eruptions jumped from 90 to 150 minutes. Because the quakes occurred up to 250 km (155 miles) from the geyser, the data are not very helpful in warning the public, but they do support the idea that earthquakes result from underground stresses ranging over wide areas, not just along local faults.