Japanese seismologists believe they have confirmed a controversial technique, measuring electromagnetic signals from rocks, that hopes to predict when and where earthquakes will occur and how destructive they will be.
The method was first expounded by a trio of Greek scientists five years ago, who suggested that rocks being ground together under immense stress emit tell-tale electrical waves and magnetic pulses.
But many experts have been scornful because, until now, no one has been able to replicate their results.
But Tokai University’s Earthquake Prediction Research Centre say they now have data to back the Greeks’ claims, the British weekly New Scientist reports in next Saturday’s issue.
Using telephone wires as antennae, they spotted anomalous changes in electromagnetic waves in Japan’s Izu islands in March 2000.
These waves, in the extremely low part of the energy spectrum, grew steadily until, three months later, a series of earthquakes occurred.
The signals peaked just before the first large quake, measuring 6,4 on the Richter scale, which occurred on July 1.
When the quakes died away, so did the waves.
The team also saw a tiny variation in the Earth’s magnetic field that they believe cannot be explained by man-made or natural sources.
The researchers are convinced they saw ”clear, unusual changes” in the geo-electrical field that help the predictive effort, but admit the picture is still unclear.
The signals were puzzlingly picked up at only two antennae, which could mean that they are detectable only in certain areas, perhaps being transmitted through water-holding faults in the rock.
The study is published in the US journal Proceedings of the National Academy of Sciences (PNAS).
The wrangle among seismologists is unlikely to subside, however. Max Wyss of the University of Alaska at Fairbanks dismisses the Japanese measurements as ”grasping at straws.”
”They simply want to believe that, no matter what the facts are,” Wyss told New Scientist. – Sapa-AFP