Scientists can predict quake effects within seconds

By Nicholas Rigillo Dec 14, 2006, 15:13 GMT

Rome - Italian scientists say they can now predict the destructive powers of an earthquake just seconds after the start of a tremor, thus providing a potentially life-saving advance warning to affected populations.

Researchers at the University of Naples and at the National Institute of Geophysics and Vulcanology (INGV) in Rome analysed more than 200 earthquakes with magnitudes ranging from 4.0 to 7.4 on the Richter scale and found that the waves generated in the first few seconds of a tremor carry enough information to determine its destructive potential.

So-called primary (P) waves travel at around six kilometres per hour, about one and a half times faster than the more destructive secondary (S) waves, while the even slower surface waves carry a highly damaging potential.

This means residents in a town located 60 kilometres from the quake's epicentre could have at least 15-seconds to prepare, if automated early warning systems were in place.

The study, which confirms and refines previous findings carried out by researchers at the University of California, Berkeley, was to be published on Friday by the scientific journal Geophysical Research Letters.

A few seconds' warning might not sound like much, but it could make all the difference, researchers say.

On January 17, 1995, for instance, an earthquake measuring 7.2 on the Richter scale hit the Japanese city of Kobe, killing more than 6,000 people. Some of the victims were driving on the elevated Hanshin motorway, which collapsed in three places as a result of the quake, throwing 50 cars off the edge.

Since the quake's epicentre was located about 20 kilometres away from Kobe, an automated system may have had enough time to shut down road to incoming traffic and save some lives.

And while a handful of seconds might not be enough to allow people to run for shelter, they could be sufficient to close down nuclear plants and gas lines or stop speeding trains.

'We still cannot predict earthquakes, but we can estimate their likely magnitude right at the beginning of a rupture,' Stefan Nielsen, one of the study's authors, told Deutsche Presse Agentur dpa.

Currently, it takes about five minutes for experts to locate an earthquake, measure its approximate magnitude and transmit the information to civil protection agencies.

If the Italian study is confirmed, it could significantly reduce lag times and speed up rescue or preventive operations.