Predicting earthquakes from space

THE HINDU [FEB. 8, 2001]

SCIENTISTS OF the Department of Physics, Moscow State University, have proposed to predict earthquakes by measuring polarization of the solar light that is reflected from the surface of the Earth. The small and cheap equipment, which the scientists have designed, can be placed on meteorological satellites.

Polarization of solar light at reflecting from the surface of planets was discovered by Domenic Francois Aragoe in the XIX century. The scientists have recently proposed to apply this phenomenon to predict earthquakes. The matter is that the polarization of the reflected light is significantly influenced by disturbances of the geo-electric field, which are observed in the areas where earthquakes can happen soon. These disturbances are considered to be the most reliable indicators of earthquakes in spite of the fact that their physical origin is not clear.

Some time before an earthquake redistribution of pressure occurs inside the planet and especially near the surface. As a result, in these areas surplus charges appear and the geo-electric field changes. This phenomenon is called baroelectric effect. Therefore, to predict earthquakes it is enough to place a number of the observation points to monitor the magnetic and electric fields of the Earth.

However it is technically difficult and expensive. Is it possible to fix the changes in geo-electric field in different areas of the Earth using another method? It turned out that it could be done indirectly by observing the changes in polarization of the solar light reflected from the surface of the Earth. The polarization always changes in the areas where intensity of the electric field increases. These changes can easily be found with the specialized devices.

The scientists have assessed the typical anomalous pressures that are able to cause the breaks of bedrock. They have also calculated an increase in the intensity of the geo-electric field in the areas of breaks and the polarization of the reflected light. In such a way if you can monitor the changing polarization of the light reflected from different parts of the Earth surface and find the places where the polarization changes quickly, you can predict earthquakes.