August 9, 2008

Lights, Camera, Earthquake?

By Coffin, Bill

Just 30 minutes before the earthquake that killed tens of thousands in the Chinese province of Sichuan in May, local video footage captured on a cell phone revealed rainbow lights in the clouds. Some have identified the lights as merely a circumhorizontal arc-an unusual, horizontal rainbow refracting through ice crystals in cirrus clouds. Others, however, consider the light show an example of "earthquake lights," a scientifically unproven indicator of a coming earthquake. The theory behind earthquake lights is that seismic activity sends ultrasonic waves through mineral deposits in the earth's crust. These waves react with water molecules in the sky to produce a rainbow effect in clouds. The scientific evidence for this is dubious at best. That said, earthquake lights are just one of a number of anecdotal methods for predicting quakes, and some of them have had interesting results.

Animal behavior, for example, is the best-known precursor. Before a quake, it is said that dogs howl, cats hide and livestock spook. One explanation claims that animals sense low frequency vibrations through the earth that put them on alert. In 1975, Chinese officials evacuated the city of Haicheng in part because of a series of foreshocks in the area, but also because of observations of typical pre-earthquake animal behavior. A magnitude 7.3 quake occurred days later and an estimated 150,000 would have died had the city not been evacuated. Around the same time, the United States Geologic Service conducted a few studies on strange animal behavior prior to quakes, but they were inconclusive.

Another quake prediction wives' tale is earthquake clouds, a theory championed by retired Chinese chemist Zhonghao Shou, who now lives in New York. Since 1994, he has predicted earthquakes through satellite images of cloud patterns. He claims to have a 70% accuracy rate, including predicting the earthquake that leveled Bam, Iran in 2004, killing nearly 25,000. The theory is that seismic activity vaporizes water long before an earthquake occurs, creating unusual and distinctly shaped cloud patterns. Where these cloud patterns form, a quake is likely to occur within 30 days. While most seismologists dismiss Shou's conclusions, he has been invited to workshops by the United Nations and the Iranian Space Agency, and some consider his work to merit further study.

Copyright Risk Management Society Publishing, Inc. Jul 2008


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